# HG changeset patch
# User John W. Eaton <jwe@octave.org>
# Date 1383851038 18000
# Node ID 0d660785098ef172aded9f8d63057fc703cd7290
# Parent  540d1c122b087cb4a0f76c5e1c867c6ef33029cf
work around GCC bug in stl_algo.h (nth_element and sort; bug #40436)

* build-aux/stl_algo.h-fixed: New file.
* acinclude.m4 (OCTAVE_CHECK_BROKEN_STL_ALGO_H): New macro.
* configure.ac: Use it.  Set AMCOND_HAVE_BROKEN_STL_ALGO_H.
* Makefile.am (bits/stl_algo.h): New target.
(BUILT_SOURCES): Add bits/stl_algo.h to the list if
AMCOND_HAVE_BROKEN_STL_ALGO_H is true.
(EXTRA_DIST): Include built-aux/stl_algo.h-fixed in the list.

diff -r 540d1c122b08 -r 0d660785098e Makefile.am
--- a/Makefile.am	Thu Nov 07 12:37:13 2013 -0500
+++ b/Makefile.am	Thu Nov 07 14:03:58 2013 -0500
@@ -44,6 +44,7 @@
   build-aux/mk-opts.pl \
   build-aux/move-if-change \
   build-aux/OctJavaQry.class \
+  build-aux/stl_algo.h-fixed \
   etc/NEWS.1 \
   etc/NEWS.2 \
   etc/NEWS.3 \
@@ -92,6 +93,10 @@
 
 BUILT_SOURCES = run-octave
 
+if AMCOND_HAVE_BROKEN_STL_ALGO_H
+  BUILT_SOURCES += bits/stl_algo.h
+endif
+
 noinst_SCRIPTS = run-octave
 
 INFO_FILES = \
@@ -128,6 +133,10 @@
 	@$(do_subst_script_vals)
 	chmod a+rx "$@"
 
+bits/stl_algo.h: build-aux/stl_algo.h-fixed
+	$(MKDIR_P) bits
+	$(INSTALL_HEADER) $< $@
+
 .gdbinit: etc/gdbinit
 	@$(gdbinit_install_rule)
 
diff -r 540d1c122b08 -r 0d660785098e build-aux/stl_algo.h-fixed
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/build-aux/stl_algo.h-fixed	Thu Nov 07 14:03:58 2013 -0500
@@ -0,0 +1,6324 @@
+// Algorithm implementation -*- C++ -*-
+
+// Copyright (C) 2001-2013 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/*
+ *
+ * Copyright (c) 1994
+ * Hewlett-Packard Company
+ *
+ * Permission to use, copy, modify, distribute and sell this software
+ * and its documentation for any purpose is hereby granted without fee,
+ * provided that the above copyright notice appear in all copies and
+ * that both that copyright notice and this permission notice appear
+ * in supporting documentation.  Hewlett-Packard Company makes no
+ * representations about the suitability of this software for any
+ * purpose.  It is provided "as is" without express or implied warranty.
+ *
+ *
+ * Copyright (c) 1996
+ * Silicon Graphics Computer Systems, Inc.
+ *
+ * Permission to use, copy, modify, distribute and sell this software
+ * and its documentation for any purpose is hereby granted without fee,
+ * provided that the above copyright notice appear in all copies and
+ * that both that copyright notice and this permission notice appear
+ * in supporting documentation.  Silicon Graphics makes no
+ * representations about the suitability of this software for any
+ * purpose.  It is provided "as is" without express or implied warranty.
+ */
+
+/** @file bits/stl_algo.h
+ *  This is an internal header file, included by other library headers.
+ *  Do not attempt to use it directly. @headername{algorithm}
+ */
+
+#ifndef _STL_ALGO_H
+#define _STL_ALGO_H 1
+
+#include <cstdlib>             // for rand
+#include <bits/algorithmfwd.h>
+#include <bits/stl_heap.h>
+#include <bits/stl_tempbuf.h>  // for _Temporary_buffer
+
+#if __cplusplus >= 201103L
+#include <random>     // for std::uniform_int_distribution
+#include <functional> // for std::bind
+#endif
+
+// See concept_check.h for the __glibcxx_*_requires macros.
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+  /// Swaps the median value of *__a, *__b and *__c to *__result
+  template<typename _Iterator>
+    void
+    __move_median_to_first(_Iterator __result, _Iterator __a,
+			   _Iterator __b, _Iterator __c)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_LessThanComparableConcept<
+	    typename iterator_traits<_Iterator>::value_type>)
+
+      if (*__a < *__b)
+	{
+	  if (*__b < *__c)
+	    std::iter_swap(__result, __b);
+	  else if (*__a < *__c)
+	    std::iter_swap(__result, __c);
+	  else
+	    std::iter_swap(__result, __a);
+	}
+      else if (*__a < *__c)
+      	std::iter_swap(__result, __a);
+      else if (*__b < *__c)
+	std::iter_swap(__result, __c);
+      else
+	std::iter_swap(__result, __b);
+    }
+
+  /// Swaps the median value of *__a, *__b and *__c under __comp to *__result
+  template<typename _Iterator, typename _Compare>
+    void
+    __move_median_to_first(_Iterator __result, _Iterator __a,
+			   _Iterator __b, _Iterator __c,
+			   _Compare __comp)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_BinaryFunctionConcept<_Compare, bool,
+	    typename iterator_traits<_Iterator>::value_type,
+	    typename iterator_traits<_Iterator>::value_type>)
+
+      if (__comp(*__a, *__b))
+	{
+	  if (__comp(*__b, *__c))
+	    std::iter_swap(__result, __b);
+	  else if (__comp(*__a, *__c))
+	    std::iter_swap(__result, __c);
+	  else
+	    std::iter_swap(__result, __a);
+	}
+      else if (__comp(*__a, *__c))
+	std::iter_swap(__result, __a);
+      else if (__comp(*__b, *__c))
+	std::iter_swap(__result, __c);
+      else
+	std::iter_swap(__result, __b);
+    }
+
+  // for_each
+
+  /// This is an overload used by find() for the Input Iterator case.
+  template<typename _InputIterator, typename _Tp>
+    inline _InputIterator
+    __find(_InputIterator __first, _InputIterator __last,
+	   const _Tp& __val, input_iterator_tag)
+    {
+      while (__first != __last && !(*__first == __val))
+	++__first;
+      return __first;
+    }
+
+  /// This is an overload used by find_if() for the Input Iterator case.
+  template<typename _InputIterator, typename _Predicate>
+    inline _InputIterator
+    __find_if(_InputIterator __first, _InputIterator __last,
+	      _Predicate __pred, input_iterator_tag)
+    {
+      while (__first != __last && !bool(__pred(*__first)))
+	++__first;
+      return __first;
+    }
+
+  /// This is an overload used by find() for the RAI case.
+  template<typename _RandomAccessIterator, typename _Tp>
+    _RandomAccessIterator
+    __find(_RandomAccessIterator __first, _RandomAccessIterator __last,
+	   const _Tp& __val, random_access_iterator_tag)
+    {
+      typename iterator_traits<_RandomAccessIterator>::difference_type
+	__trip_count = (__last - __first) >> 2;
+
+      for (; __trip_count > 0; --__trip_count)
+	{
+	  if (*__first == __val)
+	    return __first;
+	  ++__first;
+
+	  if (*__first == __val)
+	    return __first;
+	  ++__first;
+
+	  if (*__first == __val)
+	    return __first;
+	  ++__first;
+
+	  if (*__first == __val)
+	    return __first;
+	  ++__first;
+	}
+
+      switch (__last - __first)
+	{
+	case 3:
+	  if (*__first == __val)
+	    return __first;
+	  ++__first;
+	case 2:
+	  if (*__first == __val)
+	    return __first;
+	  ++__first;
+	case 1:
+	  if (*__first == __val)
+	    return __first;
+	  ++__first;
+	case 0:
+	default:
+	  return __last;
+	}
+    }
+
+  /// This is an overload used by find_if() for the RAI case.
+  template<typename _RandomAccessIterator, typename _Predicate>
+    _RandomAccessIterator
+    __find_if(_RandomAccessIterator __first, _RandomAccessIterator __last,
+	      _Predicate __pred, random_access_iterator_tag)
+    {
+      typename iterator_traits<_RandomAccessIterator>::difference_type
+	__trip_count = (__last - __first) >> 2;
+
+      for (; __trip_count > 0; --__trip_count)
+	{
+	  if (__pred(*__first))
+	    return __first;
+	  ++__first;
+
+	  if (__pred(*__first))
+	    return __first;
+	  ++__first;
+
+	  if (__pred(*__first))
+	    return __first;
+	  ++__first;
+
+	  if (__pred(*__first))
+	    return __first;
+	  ++__first;
+	}
+
+      switch (__last - __first)
+	{
+	case 3:
+	  if (__pred(*__first))
+	    return __first;
+	  ++__first;
+	case 2:
+	  if (__pred(*__first))
+	    return __first;
+	  ++__first;
+	case 1:
+	  if (__pred(*__first))
+	    return __first;
+	  ++__first;
+	case 0:
+	default:
+	  return __last;
+	}
+    }
+
+  /// This is an overload used by find_if_not() for the Input Iterator case.
+  template<typename _InputIterator, typename _Predicate>
+    inline _InputIterator
+    __find_if_not(_InputIterator __first, _InputIterator __last,
+		  _Predicate __pred, input_iterator_tag)
+    {
+      while (__first != __last && bool(__pred(*__first)))
+	++__first;
+      return __first;
+    }
+
+  /// This is an overload used by find_if_not() for the RAI case.
+  template<typename _RandomAccessIterator, typename _Predicate>
+    _RandomAccessIterator
+    __find_if_not(_RandomAccessIterator __first, _RandomAccessIterator __last,
+		  _Predicate __pred, random_access_iterator_tag)
+    {
+      typename iterator_traits<_RandomAccessIterator>::difference_type
+	__trip_count = (__last - __first) >> 2;
+
+      for (; __trip_count > 0; --__trip_count)
+	{
+	  if (!bool(__pred(*__first)))
+	    return __first;
+	  ++__first;
+
+	  if (!bool(__pred(*__first)))
+	    return __first;
+	  ++__first;
+
+	  if (!bool(__pred(*__first)))
+	    return __first;
+	  ++__first;
+
+	  if (!bool(__pred(*__first)))
+	    return __first;
+	  ++__first;
+	}
+
+      switch (__last - __first)
+	{
+	case 3:
+	  if (!bool(__pred(*__first)))
+	    return __first;
+	  ++__first;
+	case 2:
+	  if (!bool(__pred(*__first)))
+	    return __first;
+	  ++__first;
+	case 1:
+	  if (!bool(__pred(*__first)))
+	    return __first;
+	  ++__first;
+	case 0:
+	default:
+	  return __last;
+	}
+    }
+
+  /// Provided for stable_partition to use.
+  template<typename _InputIterator, typename _Predicate>
+    inline _InputIterator
+    __find_if_not(_InputIterator __first, _InputIterator __last,
+		  _Predicate __pred)
+    {
+      return std::__find_if_not(__first, __last, __pred,
+				std::__iterator_category(__first));
+    }
+
+  /// Like find_if_not(), but uses and updates a count of the
+  /// remaining range length instead of comparing against an end
+  /// iterator.
+  template<typename _InputIterator, typename _Predicate, typename _Distance>
+    _InputIterator
+    __find_if_not_n(_InputIterator __first, _Distance& __len, _Predicate __pred)
+    {
+      for (; __len; --__len, ++__first)
+	if (!bool(__pred(*__first)))
+	  break;
+      return __first;
+    }
+
+  // set_difference
+  // set_intersection
+  // set_symmetric_difference
+  // set_union
+  // for_each
+  // find
+  // find_if
+  // find_first_of
+  // adjacent_find
+  // count
+  // count_if
+  // search
+
+  /**
+   *  This is an uglified
+   *  search_n(_ForwardIterator, _ForwardIterator, _Integer, const _Tp&)
+   *  overloaded for forward iterators.
+  */
+  template<typename _ForwardIterator, typename _Integer, typename _Tp>
+    _ForwardIterator
+    __search_n(_ForwardIterator __first, _ForwardIterator __last,
+	       _Integer __count, const _Tp& __val,
+	       std::forward_iterator_tag)
+    {
+      __first = _GLIBCXX_STD_A::find(__first, __last, __val);
+      while (__first != __last)
+	{
+	  typename iterator_traits<_ForwardIterator>::difference_type
+	    __n = __count;
+	  _ForwardIterator __i = __first;
+	  ++__i;
+	  while (__i != __last && __n != 1 && *__i == __val)
+	    {
+	      ++__i;
+	      --__n;
+	    }
+	  if (__n == 1)
+	    return __first;
+	  if (__i == __last)
+	    return __last;
+	  __first = _GLIBCXX_STD_A::find(++__i, __last, __val);
+	}
+      return __last;
+    }
+
+  /**
+   *  This is an uglified
+   *  search_n(_ForwardIterator, _ForwardIterator, _Integer, const _Tp&)
+   *  overloaded for random access iterators.
+  */
+  template<typename _RandomAccessIter, typename _Integer, typename _Tp>
+    _RandomAccessIter
+    __search_n(_RandomAccessIter __first, _RandomAccessIter __last,
+	       _Integer __count, const _Tp& __val, 
+	       std::random_access_iterator_tag)
+    {
+      
+      typedef typename std::iterator_traits<_RandomAccessIter>::difference_type
+	_DistanceType;
+
+      _DistanceType __tailSize = __last - __first;
+      _DistanceType __remainder = __count;
+
+      while (__remainder <= __tailSize) // the main loop...
+	{
+	  __first += __remainder;
+	  __tailSize -= __remainder;
+	  // __first here is always pointing to one past the last element of
+	  // next possible match.
+	  _RandomAccessIter __backTrack = __first; 
+	  while (*--__backTrack == __val)
+	    {
+	      if (--__remainder == 0)
+	        return (__first - __count); // Success
+	    }
+	  __remainder = __count + 1 - (__first - __backTrack);
+	}
+      return __last; // Failure
+    }
+
+  // search_n
+
+  /**
+   *  This is an uglified
+   *  search_n(_ForwardIterator, _ForwardIterator, _Integer, const _Tp&,
+   *	       _BinaryPredicate)
+   *  overloaded for forward iterators.
+  */
+  template<typename _ForwardIterator, typename _Integer, typename _Tp,
+           typename _BinaryPredicate>
+    _ForwardIterator
+    __search_n(_ForwardIterator __first, _ForwardIterator __last,
+	       _Integer __count, const _Tp& __val,
+	       _BinaryPredicate __binary_pred, std::forward_iterator_tag)
+    {
+      while (__first != __last && !bool(__binary_pred(*__first, __val)))
+        ++__first;
+
+      while (__first != __last)
+	{
+	  typename iterator_traits<_ForwardIterator>::difference_type
+	    __n = __count;
+	  _ForwardIterator __i = __first;
+	  ++__i;
+	  while (__i != __last && __n != 1 && bool(__binary_pred(*__i, __val)))
+	    {
+	      ++__i;
+	      --__n;
+	    }
+	  if (__n == 1)
+	    return __first;
+	  if (__i == __last)
+	    return __last;
+	  __first = ++__i;
+	  while (__first != __last
+		 && !bool(__binary_pred(*__first, __val)))
+	    ++__first;
+	}
+      return __last;
+    }
+
+  /**
+   *  This is an uglified
+   *  search_n(_ForwardIterator, _ForwardIterator, _Integer, const _Tp&,
+   *	       _BinaryPredicate)
+   *  overloaded for random access iterators.
+  */
+  template<typename _RandomAccessIter, typename _Integer, typename _Tp,
+	   typename _BinaryPredicate>
+    _RandomAccessIter
+    __search_n(_RandomAccessIter __first, _RandomAccessIter __last,
+	       _Integer __count, const _Tp& __val,
+	       _BinaryPredicate __binary_pred, std::random_access_iterator_tag)
+    {
+      
+      typedef typename std::iterator_traits<_RandomAccessIter>::difference_type
+	_DistanceType;
+
+      _DistanceType __tailSize = __last - __first;
+      _DistanceType __remainder = __count;
+
+      while (__remainder <= __tailSize) // the main loop...
+	{
+	  __first += __remainder;
+	  __tailSize -= __remainder;
+	  // __first here is always pointing to one past the last element of
+	  // next possible match.
+	  _RandomAccessIter __backTrack = __first; 
+	  while (__binary_pred(*--__backTrack, __val))
+	    {
+	      if (--__remainder == 0)
+	        return (__first - __count); // Success
+	    }
+	  __remainder = __count + 1 - (__first - __backTrack);
+	}
+      return __last; // Failure
+    }
+
+  // find_end for forward iterators.
+  template<typename _ForwardIterator1, typename _ForwardIterator2>
+    _ForwardIterator1
+    __find_end(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
+	       _ForwardIterator2 __first2, _ForwardIterator2 __last2,
+	       forward_iterator_tag, forward_iterator_tag)
+    {
+      if (__first2 == __last2)
+	return __last1;
+      else
+	{
+	  _ForwardIterator1 __result = __last1;
+	  while (1)
+	    {
+	      _ForwardIterator1 __new_result
+		= _GLIBCXX_STD_A::search(__first1, __last1, __first2, __last2);
+	      if (__new_result == __last1)
+		return __result;
+	      else
+		{
+		  __result = __new_result;
+		  __first1 = __new_result;
+		  ++__first1;
+		}
+	    }
+	}
+    }
+
+  template<typename _ForwardIterator1, typename _ForwardIterator2,
+	   typename _BinaryPredicate>
+    _ForwardIterator1
+    __find_end(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
+	       _ForwardIterator2 __first2, _ForwardIterator2 __last2,
+	       forward_iterator_tag, forward_iterator_tag,
+	       _BinaryPredicate __comp)
+    {
+      if (__first2 == __last2)
+	return __last1;
+      else
+	{
+	  _ForwardIterator1 __result = __last1;
+	  while (1)
+	    {
+	      _ForwardIterator1 __new_result
+		= _GLIBCXX_STD_A::search(__first1, __last1, __first2,
+					 __last2, __comp);
+	      if (__new_result == __last1)
+		return __result;
+	      else
+		{
+		  __result = __new_result;
+		  __first1 = __new_result;
+		  ++__first1;
+		}
+	    }
+	}
+    }
+
+  // find_end for bidirectional iterators (much faster).
+  template<typename _BidirectionalIterator1, typename _BidirectionalIterator2>
+    _BidirectionalIterator1
+    __find_end(_BidirectionalIterator1 __first1,
+	       _BidirectionalIterator1 __last1,
+	       _BidirectionalIterator2 __first2,
+	       _BidirectionalIterator2 __last2,
+	       bidirectional_iterator_tag, bidirectional_iterator_tag)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_BidirectionalIteratorConcept<
+				  _BidirectionalIterator1>)
+      __glibcxx_function_requires(_BidirectionalIteratorConcept<
+				  _BidirectionalIterator2>)
+
+      typedef reverse_iterator<_BidirectionalIterator1> _RevIterator1;
+      typedef reverse_iterator<_BidirectionalIterator2> _RevIterator2;
+
+      _RevIterator1 __rlast1(__first1);
+      _RevIterator2 __rlast2(__first2);
+      _RevIterator1 __rresult = _GLIBCXX_STD_A::search(_RevIterator1(__last1),
+						       __rlast1,
+						       _RevIterator2(__last2),
+						       __rlast2);
+
+      if (__rresult == __rlast1)
+	return __last1;
+      else
+	{
+	  _BidirectionalIterator1 __result = __rresult.base();
+	  std::advance(__result, -std::distance(__first2, __last2));
+	  return __result;
+	}
+    }
+
+  template<typename _BidirectionalIterator1, typename _BidirectionalIterator2,
+	   typename _BinaryPredicate>
+    _BidirectionalIterator1
+    __find_end(_BidirectionalIterator1 __first1,
+	       _BidirectionalIterator1 __last1,
+	       _BidirectionalIterator2 __first2,
+	       _BidirectionalIterator2 __last2,
+	       bidirectional_iterator_tag, bidirectional_iterator_tag,
+	       _BinaryPredicate __comp)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_BidirectionalIteratorConcept<
+				  _BidirectionalIterator1>)
+      __glibcxx_function_requires(_BidirectionalIteratorConcept<
+				  _BidirectionalIterator2>)
+
+      typedef reverse_iterator<_BidirectionalIterator1> _RevIterator1;
+      typedef reverse_iterator<_BidirectionalIterator2> _RevIterator2;
+
+      _RevIterator1 __rlast1(__first1);
+      _RevIterator2 __rlast2(__first2);
+      _RevIterator1 __rresult = std::search(_RevIterator1(__last1), __rlast1,
+					    _RevIterator2(__last2), __rlast2,
+					    __comp);
+
+      if (__rresult == __rlast1)
+	return __last1;
+      else
+	{
+	  _BidirectionalIterator1 __result = __rresult.base();
+	  std::advance(__result, -std::distance(__first2, __last2));
+	  return __result;
+	}
+    }
+
+  /**
+   *  @brief  Find last matching subsequence in a sequence.
+   *  @ingroup non_mutating_algorithms
+   *  @param  __first1  Start of range to search.
+   *  @param  __last1   End of range to search.
+   *  @param  __first2  Start of sequence to match.
+   *  @param  __last2   End of sequence to match.
+   *  @return   The last iterator @c i in the range
+   *  @p [__first1,__last1-(__last2-__first2)) such that @c *(i+N) ==
+   *  @p *(__first2+N) for each @c N in the range @p
+   *  [0,__last2-__first2), or @p __last1 if no such iterator exists.
+   *
+   *  Searches the range @p [__first1,__last1) for a sub-sequence that
+   *  compares equal value-by-value with the sequence given by @p
+   *  [__first2,__last2) and returns an iterator to the __first
+   *  element of the sub-sequence, or @p __last1 if the sub-sequence
+   *  is not found.  The sub-sequence will be the last such
+   *  subsequence contained in [__first,__last1).
+   *
+   *  Because the sub-sequence must lie completely within the range @p
+   *  [__first1,__last1) it must start at a position less than @p
+   *  __last1-(__last2-__first2) where @p __last2-__first2 is the
+   *  length of the sub-sequence.  This means that the returned
+   *  iterator @c i will be in the range @p
+   *  [__first1,__last1-(__last2-__first2))
+  */
+  template<typename _ForwardIterator1, typename _ForwardIterator2>
+    inline _ForwardIterator1
+    find_end(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
+	     _ForwardIterator2 __first2, _ForwardIterator2 __last2)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator1>)
+      __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator2>)
+      __glibcxx_function_requires(_EqualOpConcept<
+	    typename iterator_traits<_ForwardIterator1>::value_type,
+	    typename iterator_traits<_ForwardIterator2>::value_type>)
+      __glibcxx_requires_valid_range(__first1, __last1);
+      __glibcxx_requires_valid_range(__first2, __last2);
+
+      return std::__find_end(__first1, __last1, __first2, __last2,
+			     std::__iterator_category(__first1),
+			     std::__iterator_category(__first2));
+    }
+
+  /**
+   *  @brief  Find last matching subsequence in a sequence using a predicate.
+   *  @ingroup non_mutating_algorithms
+   *  @param  __first1  Start of range to search.
+   *  @param  __last1   End of range to search.
+   *  @param  __first2  Start of sequence to match.
+   *  @param  __last2   End of sequence to match.
+   *  @param  __comp    The predicate to use.
+   *  @return The last iterator @c i in the range @p
+   *  [__first1,__last1-(__last2-__first2)) such that @c
+   *  predicate(*(i+N), @p (__first2+N)) is true for each @c N in the
+   *  range @p [0,__last2-__first2), or @p __last1 if no such iterator
+   *  exists.
+   *
+   *  Searches the range @p [__first1,__last1) for a sub-sequence that
+   *  compares equal value-by-value with the sequence given by @p
+   *  [__first2,__last2) using comp as a predicate and returns an
+   *  iterator to the first element of the sub-sequence, or @p __last1
+   *  if the sub-sequence is not found.  The sub-sequence will be the
+   *  last such subsequence contained in [__first,__last1).
+   *
+   *  Because the sub-sequence must lie completely within the range @p
+   *  [__first1,__last1) it must start at a position less than @p
+   *  __last1-(__last2-__first2) where @p __last2-__first2 is the
+   *  length of the sub-sequence.  This means that the returned
+   *  iterator @c i will be in the range @p
+   *  [__first1,__last1-(__last2-__first2))
+  */
+  template<typename _ForwardIterator1, typename _ForwardIterator2,
+	   typename _BinaryPredicate>
+    inline _ForwardIterator1
+    find_end(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
+	     _ForwardIterator2 __first2, _ForwardIterator2 __last2,
+	     _BinaryPredicate __comp)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator1>)
+      __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator2>)
+      __glibcxx_function_requires(_BinaryPredicateConcept<_BinaryPredicate,
+	    typename iterator_traits<_ForwardIterator1>::value_type,
+	    typename iterator_traits<_ForwardIterator2>::value_type>)
+      __glibcxx_requires_valid_range(__first1, __last1);
+      __glibcxx_requires_valid_range(__first2, __last2);
+
+      return std::__find_end(__first1, __last1, __first2, __last2,
+			     std::__iterator_category(__first1),
+			     std::__iterator_category(__first2),
+			     __comp);
+    }
+
+#if __cplusplus >= 201103L
+  /**
+   *  @brief  Checks that a predicate is true for all the elements
+   *          of a sequence.
+   *  @ingroup non_mutating_algorithms
+   *  @param  __first   An input iterator.
+   *  @param  __last    An input iterator.
+   *  @param  __pred    A predicate.
+   *  @return  True if the check is true, false otherwise.
+   *
+   *  Returns true if @p __pred is true for each element in the range
+   *  @p [__first,__last), and false otherwise.
+  */
+  template<typename _InputIterator, typename _Predicate>
+    inline bool
+    all_of(_InputIterator __first, _InputIterator __last, _Predicate __pred)
+    { return __last == std::find_if_not(__first, __last, __pred); }
+
+  /**
+   *  @brief  Checks that a predicate is false for all the elements
+   *          of a sequence.
+   *  @ingroup non_mutating_algorithms
+   *  @param  __first   An input iterator.
+   *  @param  __last    An input iterator.
+   *  @param  __pred    A predicate.
+   *  @return  True if the check is true, false otherwise.
+   *
+   *  Returns true if @p __pred is false for each element in the range
+   *  @p [__first,__last), and false otherwise.
+  */
+  template<typename _InputIterator, typename _Predicate>
+    inline bool
+    none_of(_InputIterator __first, _InputIterator __last, _Predicate __pred)
+    { return __last == _GLIBCXX_STD_A::find_if(__first, __last, __pred); }
+
+  /**
+   *  @brief  Checks that a predicate is false for at least an element
+   *          of a sequence.
+   *  @ingroup non_mutating_algorithms
+   *  @param  __first   An input iterator.
+   *  @param  __last    An input iterator.
+   *  @param  __pred    A predicate.
+   *  @return  True if the check is true, false otherwise.
+   *
+   *  Returns true if an element exists in the range @p
+   *  [__first,__last) such that @p __pred is true, and false
+   *  otherwise.
+  */
+  template<typename _InputIterator, typename _Predicate>
+    inline bool
+    any_of(_InputIterator __first, _InputIterator __last, _Predicate __pred)
+    { return !std::none_of(__first, __last, __pred); }
+
+  /**
+   *  @brief  Find the first element in a sequence for which a
+   *          predicate is false.
+   *  @ingroup non_mutating_algorithms
+   *  @param  __first  An input iterator.
+   *  @param  __last   An input iterator.
+   *  @param  __pred   A predicate.
+   *  @return   The first iterator @c i in the range @p [__first,__last)
+   *  such that @p __pred(*i) is false, or @p __last if no such iterator exists.
+  */
+  template<typename _InputIterator, typename _Predicate>
+    inline _InputIterator
+    find_if_not(_InputIterator __first, _InputIterator __last,
+		_Predicate __pred)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)
+      __glibcxx_function_requires(_UnaryPredicateConcept<_Predicate,
+	      typename iterator_traits<_InputIterator>::value_type>)
+      __glibcxx_requires_valid_range(__first, __last);
+      return std::__find_if_not(__first, __last, __pred);
+    }
+
+  /**
+   *  @brief  Checks whether the sequence is partitioned.
+   *  @ingroup mutating_algorithms
+   *  @param  __first  An input iterator.
+   *  @param  __last   An input iterator.
+   *  @param  __pred   A predicate.
+   *  @return  True if the range @p [__first,__last) is partioned by @p __pred,
+   *  i.e. if all elements that satisfy @p __pred appear before those that
+   *  do not.
+  */
+  template<typename _InputIterator, typename _Predicate>
+    inline bool
+    is_partitioned(_InputIterator __first, _InputIterator __last,
+		   _Predicate __pred)
+    {
+      __first = std::find_if_not(__first, __last, __pred);
+      return std::none_of(__first, __last, __pred);
+    }
+
+  /**
+   *  @brief  Find the partition point of a partitioned range.
+   *  @ingroup mutating_algorithms
+   *  @param  __first   An iterator.
+   *  @param  __last    Another iterator.
+   *  @param  __pred    A predicate.
+   *  @return  An iterator @p mid such that @p all_of(__first, mid, __pred)
+   *           and @p none_of(mid, __last, __pred) are both true.
+  */
+  template<typename _ForwardIterator, typename _Predicate>
+    _ForwardIterator
+    partition_point(_ForwardIterator __first, _ForwardIterator __last,
+		    _Predicate __pred)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)
+      __glibcxx_function_requires(_UnaryPredicateConcept<_Predicate,
+	      typename iterator_traits<_ForwardIterator>::value_type>)
+
+      // A specific debug-mode test will be necessary...
+      __glibcxx_requires_valid_range(__first, __last);
+
+      typedef typename iterator_traits<_ForwardIterator>::difference_type
+	_DistanceType;
+
+      _DistanceType __len = std::distance(__first, __last);
+      _DistanceType __half;
+      _ForwardIterator __middle;
+
+      while (__len > 0)
+	{
+	  __half = __len >> 1;
+	  __middle = __first;
+	  std::advance(__middle, __half);
+	  if (__pred(*__middle))
+	    {
+	      __first = __middle;
+	      ++__first;
+	      __len = __len - __half - 1;
+	    }
+	  else
+	    __len = __half;
+	}
+      return __first;
+    }
+#endif
+
+
+  /**
+   *  @brief Copy a sequence, removing elements of a given value.
+   *  @ingroup mutating_algorithms
+   *  @param  __first   An input iterator.
+   *  @param  __last    An input iterator.
+   *  @param  __result  An output iterator.
+   *  @param  __value   The value to be removed.
+   *  @return   An iterator designating the end of the resulting sequence.
+   *
+   *  Copies each element in the range @p [__first,__last) not equal
+   *  to @p __value to the range beginning at @p __result.
+   *  remove_copy() is stable, so the relative order of elements that
+   *  are copied is unchanged.
+  */
+  template<typename _InputIterator, typename _OutputIterator, typename _Tp>
+    _OutputIterator
+    remove_copy(_InputIterator __first, _InputIterator __last,
+		_OutputIterator __result, const _Tp& __value)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)
+      __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,
+	    typename iterator_traits<_InputIterator>::value_type>)
+      __glibcxx_function_requires(_EqualOpConcept<
+	    typename iterator_traits<_InputIterator>::value_type, _Tp>)
+      __glibcxx_requires_valid_range(__first, __last);
+
+      for (; __first != __last; ++__first)
+	if (!(*__first == __value))
+	  {
+	    *__result = *__first;
+	    ++__result;
+	  }
+      return __result;
+    }
+
+  /**
+   *  @brief Copy a sequence, removing elements for which a predicate is true.
+   *  @ingroup mutating_algorithms
+   *  @param  __first   An input iterator.
+   *  @param  __last    An input iterator.
+   *  @param  __result  An output iterator.
+   *  @param  __pred    A predicate.
+   *  @return   An iterator designating the end of the resulting sequence.
+   *
+   *  Copies each element in the range @p [__first,__last) for which
+   *  @p __pred returns false to the range beginning at @p __result.
+   *
+   *  remove_copy_if() is stable, so the relative order of elements that are
+   *  copied is unchanged.
+  */
+  template<typename _InputIterator, typename _OutputIterator,
+	   typename _Predicate>
+    _OutputIterator
+    remove_copy_if(_InputIterator __first, _InputIterator __last,
+		   _OutputIterator __result, _Predicate __pred)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)
+      __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,
+	    typename iterator_traits<_InputIterator>::value_type>)
+      __glibcxx_function_requires(_UnaryPredicateConcept<_Predicate,
+	    typename iterator_traits<_InputIterator>::value_type>)
+      __glibcxx_requires_valid_range(__first, __last);
+
+      for (; __first != __last; ++__first)
+	if (!bool(__pred(*__first)))
+	  {
+	    *__result = *__first;
+	    ++__result;
+	  }
+      return __result;
+    }
+
+#if __cplusplus >= 201103L
+  /**
+   *  @brief Copy the elements of a sequence for which a predicate is true.
+   *  @ingroup mutating_algorithms
+   *  @param  __first   An input iterator.
+   *  @param  __last    An input iterator.
+   *  @param  __result  An output iterator.
+   *  @param  __pred    A predicate.
+   *  @return   An iterator designating the end of the resulting sequence.
+   *
+   *  Copies each element in the range @p [__first,__last) for which
+   *  @p __pred returns true to the range beginning at @p __result.
+   *
+   *  copy_if() is stable, so the relative order of elements that are
+   *  copied is unchanged.
+  */
+  template<typename _InputIterator, typename _OutputIterator,
+	   typename _Predicate>
+    _OutputIterator
+    copy_if(_InputIterator __first, _InputIterator __last,
+	    _OutputIterator __result, _Predicate __pred)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)
+      __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,
+	    typename iterator_traits<_InputIterator>::value_type>)
+      __glibcxx_function_requires(_UnaryPredicateConcept<_Predicate,
+	    typename iterator_traits<_InputIterator>::value_type>)
+      __glibcxx_requires_valid_range(__first, __last);
+
+      for (; __first != __last; ++__first)
+	if (__pred(*__first))
+	  {
+	    *__result = *__first;
+	    ++__result;
+	  }
+      return __result;
+    }
+
+
+  template<typename _InputIterator, typename _Size, typename _OutputIterator>
+    _OutputIterator
+    __copy_n(_InputIterator __first, _Size __n,
+	     _OutputIterator __result, input_iterator_tag)
+    {
+      if (__n > 0)
+	{
+	  while (true)
+	    {
+	      *__result = *__first;
+	      ++__result;
+	      if (--__n > 0)
+		++__first;
+	      else
+		break;
+	    }
+	}
+      return __result;
+    }
+
+  template<typename _RandomAccessIterator, typename _Size,
+	   typename _OutputIterator>
+    inline _OutputIterator
+    __copy_n(_RandomAccessIterator __first, _Size __n,
+	     _OutputIterator __result, random_access_iterator_tag)
+    { return std::copy(__first, __first + __n, __result); }
+
+  /**
+   *  @brief Copies the range [first,first+n) into [result,result+n).
+   *  @ingroup mutating_algorithms
+   *  @param  __first  An input iterator.
+   *  @param  __n      The number of elements to copy.
+   *  @param  __result An output iterator.
+   *  @return  result+n.
+   *
+   *  This inline function will boil down to a call to @c memmove whenever
+   *  possible.  Failing that, if random access iterators are passed, then the
+   *  loop count will be known (and therefore a candidate for compiler
+   *  optimizations such as unrolling).
+  */
+  template<typename _InputIterator, typename _Size, typename _OutputIterator>
+    inline _OutputIterator
+    copy_n(_InputIterator __first, _Size __n, _OutputIterator __result)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)
+      __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,
+	    typename iterator_traits<_InputIterator>::value_type>)
+
+      return std::__copy_n(__first, __n, __result,
+			   std::__iterator_category(__first));
+    }
+
+  /**
+   *  @brief Copy the elements of a sequence to separate output sequences
+   *         depending on the truth value of a predicate.
+   *  @ingroup mutating_algorithms
+   *  @param  __first   An input iterator.
+   *  @param  __last    An input iterator.
+   *  @param  __out_true   An output iterator.
+   *  @param  __out_false  An output iterator.
+   *  @param  __pred    A predicate.
+   *  @return   A pair designating the ends of the resulting sequences.
+   *
+   *  Copies each element in the range @p [__first,__last) for which
+   *  @p __pred returns true to the range beginning at @p out_true
+   *  and each element for which @p __pred returns false to @p __out_false.
+  */
+  template<typename _InputIterator, typename _OutputIterator1,
+	   typename _OutputIterator2, typename _Predicate>
+    pair<_OutputIterator1, _OutputIterator2>
+    partition_copy(_InputIterator __first, _InputIterator __last,
+		   _OutputIterator1 __out_true, _OutputIterator2 __out_false,
+		   _Predicate __pred)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)
+      __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator1,
+	    typename iterator_traits<_InputIterator>::value_type>)
+      __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator2,
+	    typename iterator_traits<_InputIterator>::value_type>)
+      __glibcxx_function_requires(_UnaryPredicateConcept<_Predicate,
+	    typename iterator_traits<_InputIterator>::value_type>)
+      __glibcxx_requires_valid_range(__first, __last);
+      
+      for (; __first != __last; ++__first)
+	if (__pred(*__first))
+	  {
+	    *__out_true = *__first;
+	    ++__out_true;
+	  }
+	else
+	  {
+	    *__out_false = *__first;
+	    ++__out_false;
+	  }
+
+      return pair<_OutputIterator1, _OutputIterator2>(__out_true, __out_false);
+    }
+#endif
+
+  /**
+   *  @brief Remove elements from a sequence.
+   *  @ingroup mutating_algorithms
+   *  @param  __first  An input iterator.
+   *  @param  __last   An input iterator.
+   *  @param  __value  The value to be removed.
+   *  @return   An iterator designating the end of the resulting sequence.
+   *
+   *  All elements equal to @p __value are removed from the range
+   *  @p [__first,__last).
+   *
+   *  remove() is stable, so the relative order of elements that are
+   *  not removed is unchanged.
+   *
+   *  Elements between the end of the resulting sequence and @p __last
+   *  are still present, but their value is unspecified.
+  */
+  template<typename _ForwardIterator, typename _Tp>
+    _ForwardIterator
+    remove(_ForwardIterator __first, _ForwardIterator __last,
+	   const _Tp& __value)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_Mutable_ForwardIteratorConcept<
+				  _ForwardIterator>)
+      __glibcxx_function_requires(_EqualOpConcept<
+	    typename iterator_traits<_ForwardIterator>::value_type, _Tp>)
+      __glibcxx_requires_valid_range(__first, __last);
+
+      __first = _GLIBCXX_STD_A::find(__first, __last, __value);
+      if(__first == __last)
+        return __first;
+      _ForwardIterator __result = __first;
+      ++__first;
+      for(; __first != __last; ++__first)
+        if(!(*__first == __value))
+          {
+            *__result = _GLIBCXX_MOVE(*__first);
+            ++__result;
+          }
+      return __result;
+    }
+
+  /**
+   *  @brief Remove elements from a sequence using a predicate.
+   *  @ingroup mutating_algorithms
+   *  @param  __first  A forward iterator.
+   *  @param  __last   A forward iterator.
+   *  @param  __pred   A predicate.
+   *  @return   An iterator designating the end of the resulting sequence.
+   *
+   *  All elements for which @p __pred returns true are removed from the range
+   *  @p [__first,__last).
+   *
+   *  remove_if() is stable, so the relative order of elements that are
+   *  not removed is unchanged.
+   *
+   *  Elements between the end of the resulting sequence and @p __last
+   *  are still present, but their value is unspecified.
+  */
+  template<typename _ForwardIterator, typename _Predicate>
+    _ForwardIterator
+    remove_if(_ForwardIterator __first, _ForwardIterator __last,
+	      _Predicate __pred)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_Mutable_ForwardIteratorConcept<
+				  _ForwardIterator>)
+      __glibcxx_function_requires(_UnaryPredicateConcept<_Predicate,
+	    typename iterator_traits<_ForwardIterator>::value_type>)
+      __glibcxx_requires_valid_range(__first, __last);
+
+      __first = _GLIBCXX_STD_A::find_if(__first, __last, __pred);
+      if(__first == __last)
+        return __first;
+      _ForwardIterator __result = __first;
+      ++__first;
+      for(; __first != __last; ++__first)
+        if(!bool(__pred(*__first)))
+          {
+            *__result = _GLIBCXX_MOVE(*__first);
+            ++__result;
+          }
+      return __result;
+    }
+
+  /**
+   *  @brief Remove consecutive duplicate values from a sequence.
+   *  @ingroup mutating_algorithms
+   *  @param  __first  A forward iterator.
+   *  @param  __last   A forward iterator.
+   *  @return  An iterator designating the end of the resulting sequence.
+   *
+   *  Removes all but the first element from each group of consecutive
+   *  values that compare equal.
+   *  unique() is stable, so the relative order of elements that are
+   *  not removed is unchanged.
+   *  Elements between the end of the resulting sequence and @p __last
+   *  are still present, but their value is unspecified.
+  */
+  template<typename _ForwardIterator>
+    _ForwardIterator
+    unique(_ForwardIterator __first, _ForwardIterator __last)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_Mutable_ForwardIteratorConcept<
+				  _ForwardIterator>)
+      __glibcxx_function_requires(_EqualityComparableConcept<
+		     typename iterator_traits<_ForwardIterator>::value_type>)
+      __glibcxx_requires_valid_range(__first, __last);
+
+      // Skip the beginning, if already unique.
+      __first = _GLIBCXX_STD_A::adjacent_find(__first, __last);
+      if (__first == __last)
+	return __last;
+
+      // Do the real copy work.
+      _ForwardIterator __dest = __first;
+      ++__first;
+      while (++__first != __last)
+	if (!(*__dest == *__first))
+	  *++__dest = _GLIBCXX_MOVE(*__first);
+      return ++__dest;
+    }
+
+  /**
+   *  @brief Remove consecutive values from a sequence using a predicate.
+   *  @ingroup mutating_algorithms
+   *  @param  __first        A forward iterator.
+   *  @param  __last         A forward iterator.
+   *  @param  __binary_pred  A binary predicate.
+   *  @return  An iterator designating the end of the resulting sequence.
+   *
+   *  Removes all but the first element from each group of consecutive
+   *  values for which @p __binary_pred returns true.
+   *  unique() is stable, so the relative order of elements that are
+   *  not removed is unchanged.
+   *  Elements between the end of the resulting sequence and @p __last
+   *  are still present, but their value is unspecified.
+  */
+  template<typename _ForwardIterator, typename _BinaryPredicate>
+    _ForwardIterator
+    unique(_ForwardIterator __first, _ForwardIterator __last,
+           _BinaryPredicate __binary_pred)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_Mutable_ForwardIteratorConcept<
+				  _ForwardIterator>)
+      __glibcxx_function_requires(_BinaryPredicateConcept<_BinaryPredicate,
+		typename iterator_traits<_ForwardIterator>::value_type,
+		typename iterator_traits<_ForwardIterator>::value_type>)
+      __glibcxx_requires_valid_range(__first, __last);
+
+      // Skip the beginning, if already unique.
+      __first = _GLIBCXX_STD_A::adjacent_find(__first, __last, __binary_pred);
+      if (__first == __last)
+	return __last;
+
+      // Do the real copy work.
+      _ForwardIterator __dest = __first;
+      ++__first;
+      while (++__first != __last)
+	if (!bool(__binary_pred(*__dest, *__first)))
+	  *++__dest = _GLIBCXX_MOVE(*__first);
+      return ++__dest;
+    }
+
+  /**
+   *  This is an uglified unique_copy(_InputIterator, _InputIterator,
+   *                                  _OutputIterator)
+   *  overloaded for forward iterators and output iterator as result.
+  */
+  template<typename _ForwardIterator, typename _OutputIterator>
+    _OutputIterator
+    __unique_copy(_ForwardIterator __first, _ForwardIterator __last,
+		  _OutputIterator __result,
+		  forward_iterator_tag, output_iterator_tag)
+    {
+      // concept requirements -- taken care of in dispatching function
+      _ForwardIterator __next = __first;
+      *__result = *__first;
+      while (++__next != __last)
+	if (!(*__first == *__next))
+	  {
+	    __first = __next;
+	    *++__result = *__first;
+	  }
+      return ++__result;
+    }
+
+  /**
+   *  This is an uglified unique_copy(_InputIterator, _InputIterator,
+   *                                  _OutputIterator)
+   *  overloaded for input iterators and output iterator as result.
+  */
+  template<typename _InputIterator, typename _OutputIterator>
+    _OutputIterator
+    __unique_copy(_InputIterator __first, _InputIterator __last,
+		  _OutputIterator __result,
+		  input_iterator_tag, output_iterator_tag)
+    {
+      // concept requirements -- taken care of in dispatching function
+      typename iterator_traits<_InputIterator>::value_type __value = *__first;
+      *__result = __value;
+      while (++__first != __last)
+	if (!(__value == *__first))
+	  {
+	    __value = *__first;
+	    *++__result = __value;
+	  }
+      return ++__result;
+    }
+
+  /**
+   *  This is an uglified unique_copy(_InputIterator, _InputIterator,
+   *                                  _OutputIterator)
+   *  overloaded for input iterators and forward iterator as result.
+  */
+  template<typename _InputIterator, typename _ForwardIterator>
+    _ForwardIterator
+    __unique_copy(_InputIterator __first, _InputIterator __last,
+		  _ForwardIterator __result,
+		  input_iterator_tag, forward_iterator_tag)
+    {
+      // concept requirements -- taken care of in dispatching function
+      *__result = *__first;
+      while (++__first != __last)
+	if (!(*__result == *__first))
+	  *++__result = *__first;
+      return ++__result;
+    }
+
+  /**
+   *  This is an uglified
+   *  unique_copy(_InputIterator, _InputIterator, _OutputIterator,
+   *              _BinaryPredicate)
+   *  overloaded for forward iterators and output iterator as result.
+  */
+  template<typename _ForwardIterator, typename _OutputIterator,
+	   typename _BinaryPredicate>
+    _OutputIterator
+    __unique_copy(_ForwardIterator __first, _ForwardIterator __last,
+		  _OutputIterator __result, _BinaryPredicate __binary_pred,
+		  forward_iterator_tag, output_iterator_tag)
+    {
+      // concept requirements -- iterators already checked
+      __glibcxx_function_requires(_BinaryPredicateConcept<_BinaryPredicate,
+	  typename iterator_traits<_ForwardIterator>::value_type,
+	  typename iterator_traits<_ForwardIterator>::value_type>)
+
+      _ForwardIterator __next = __first;
+      *__result = *__first;
+      while (++__next != __last)
+	if (!bool(__binary_pred(*__first, *__next)))
+	  {
+	    __first = __next;
+	    *++__result = *__first;
+	  }
+      return ++__result;
+    }
+
+  /**
+   *  This is an uglified
+   *  unique_copy(_InputIterator, _InputIterator, _OutputIterator,
+   *              _BinaryPredicate)
+   *  overloaded for input iterators and output iterator as result.
+  */
+  template<typename _InputIterator, typename _OutputIterator,
+	   typename _BinaryPredicate>
+    _OutputIterator
+    __unique_copy(_InputIterator __first, _InputIterator __last,
+		  _OutputIterator __result, _BinaryPredicate __binary_pred,
+		  input_iterator_tag, output_iterator_tag)
+    {
+      // concept requirements -- iterators already checked
+      __glibcxx_function_requires(_BinaryPredicateConcept<_BinaryPredicate,
+	  typename iterator_traits<_InputIterator>::value_type,
+	  typename iterator_traits<_InputIterator>::value_type>)
+
+      typename iterator_traits<_InputIterator>::value_type __value = *__first;
+      *__result = __value;
+      while (++__first != __last)
+	if (!bool(__binary_pred(__value, *__first)))
+	  {
+	    __value = *__first;
+	    *++__result = __value;
+	  }
+      return ++__result;
+    }
+
+  /**
+   *  This is an uglified
+   *  unique_copy(_InputIterator, _InputIterator, _OutputIterator,
+   *              _BinaryPredicate)
+   *  overloaded for input iterators and forward iterator as result.
+  */
+  template<typename _InputIterator, typename _ForwardIterator,
+	   typename _BinaryPredicate>
+    _ForwardIterator
+    __unique_copy(_InputIterator __first, _InputIterator __last,
+		  _ForwardIterator __result, _BinaryPredicate __binary_pred,
+		  input_iterator_tag, forward_iterator_tag)
+    {
+      // concept requirements -- iterators already checked
+      __glibcxx_function_requires(_BinaryPredicateConcept<_BinaryPredicate,
+	  typename iterator_traits<_ForwardIterator>::value_type,
+	  typename iterator_traits<_InputIterator>::value_type>)
+
+      *__result = *__first;
+      while (++__first != __last)
+	if (!bool(__binary_pred(*__result, *__first)))
+	  *++__result = *__first;
+      return ++__result;
+    }
+
+  /**
+   *  This is an uglified reverse(_BidirectionalIterator,
+   *                              _BidirectionalIterator)
+   *  overloaded for bidirectional iterators.
+  */
+  template<typename _BidirectionalIterator>
+    void
+    __reverse(_BidirectionalIterator __first, _BidirectionalIterator __last,
+	      bidirectional_iterator_tag)
+    {
+      while (true)
+	if (__first == __last || __first == --__last)
+	  return;
+	else
+	  {
+	    std::iter_swap(__first, __last);
+	    ++__first;
+	  }
+    }
+
+  /**
+   *  This is an uglified reverse(_BidirectionalIterator,
+   *                              _BidirectionalIterator)
+   *  overloaded for random access iterators.
+  */
+  template<typename _RandomAccessIterator>
+    void
+    __reverse(_RandomAccessIterator __first, _RandomAccessIterator __last,
+	      random_access_iterator_tag)
+    {
+      if (__first == __last)
+	return;
+      --__last;
+      while (__first < __last)
+	{
+	  std::iter_swap(__first, __last);
+	  ++__first;
+	  --__last;
+	}
+    }
+
+  /**
+   *  @brief Reverse a sequence.
+   *  @ingroup mutating_algorithms
+   *  @param  __first  A bidirectional iterator.
+   *  @param  __last   A bidirectional iterator.
+   *  @return   reverse() returns no value.
+   *
+   *  Reverses the order of the elements in the range @p [__first,__last),
+   *  so that the first element becomes the last etc.
+   *  For every @c i such that @p 0<=i<=(__last-__first)/2), @p reverse()
+   *  swaps @p *(__first+i) and @p *(__last-(i+1))
+  */
+  template<typename _BidirectionalIterator>
+    inline void
+    reverse(_BidirectionalIterator __first, _BidirectionalIterator __last)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_Mutable_BidirectionalIteratorConcept<
+				  _BidirectionalIterator>)
+      __glibcxx_requires_valid_range(__first, __last);
+      std::__reverse(__first, __last, std::__iterator_category(__first));
+    }
+
+  /**
+   *  @brief Copy a sequence, reversing its elements.
+   *  @ingroup mutating_algorithms
+   *  @param  __first   A bidirectional iterator.
+   *  @param  __last    A bidirectional iterator.
+   *  @param  __result  An output iterator.
+   *  @return  An iterator designating the end of the resulting sequence.
+   *
+   *  Copies the elements in the range @p [__first,__last) to the
+   *  range @p [__result,__result+(__last-__first)) such that the
+   *  order of the elements is reversed.  For every @c i such that @p
+   *  0<=i<=(__last-__first), @p reverse_copy() performs the
+   *  assignment @p *(__result+(__last-__first)-1-i) = *(__first+i).
+   *  The ranges @p [__first,__last) and @p
+   *  [__result,__result+(__last-__first)) must not overlap.
+  */
+  template<typename _BidirectionalIterator, typename _OutputIterator>
+    _OutputIterator
+    reverse_copy(_BidirectionalIterator __first, _BidirectionalIterator __last,
+		 _OutputIterator __result)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_BidirectionalIteratorConcept<
+				  _BidirectionalIterator>)
+      __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,
+		typename iterator_traits<_BidirectionalIterator>::value_type>)
+      __glibcxx_requires_valid_range(__first, __last);
+
+      while (__first != __last)
+	{
+	  --__last;
+	  *__result = *__last;
+	  ++__result;
+	}
+      return __result;
+    }
+
+  /**
+   *  This is a helper function for the rotate algorithm specialized on RAIs.
+   *  It returns the greatest common divisor of two integer values.
+  */
+  template<typename _EuclideanRingElement>
+    _EuclideanRingElement
+    __gcd(_EuclideanRingElement __m, _EuclideanRingElement __n)
+    {
+      while (__n != 0)
+	{
+	  _EuclideanRingElement __t = __m % __n;
+	  __m = __n;
+	  __n = __t;
+	}
+      return __m;
+    }
+
+  /// This is a helper function for the rotate algorithm.
+  template<typename _ForwardIterator>
+    void
+    __rotate(_ForwardIterator __first,
+	     _ForwardIterator __middle,
+	     _ForwardIterator __last,
+	     forward_iterator_tag)
+    {
+      if (__first == __middle || __last  == __middle)
+	return;
+
+      _ForwardIterator __first2 = __middle;
+      do
+	{
+	  std::iter_swap(__first, __first2);
+	  ++__first;
+	  ++__first2;
+	  if (__first == __middle)
+	    __middle = __first2;
+	}
+      while (__first2 != __last);
+
+      __first2 = __middle;
+
+      while (__first2 != __last)
+	{
+	  std::iter_swap(__first, __first2);
+	  ++__first;
+	  ++__first2;
+	  if (__first == __middle)
+	    __middle = __first2;
+	  else if (__first2 == __last)
+	    __first2 = __middle;
+	}
+    }
+
+   /// This is a helper function for the rotate algorithm.
+  template<typename _BidirectionalIterator>
+    void
+    __rotate(_BidirectionalIterator __first,
+	     _BidirectionalIterator __middle,
+	     _BidirectionalIterator __last,
+	      bidirectional_iterator_tag)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_Mutable_BidirectionalIteratorConcept<
+				  _BidirectionalIterator>)
+
+      if (__first == __middle || __last  == __middle)
+	return;
+
+      std::__reverse(__first,  __middle, bidirectional_iterator_tag());
+      std::__reverse(__middle, __last,   bidirectional_iterator_tag());
+
+      while (__first != __middle && __middle != __last)
+	{
+	  std::iter_swap(__first, --__last);
+	  ++__first;
+	}
+
+      if (__first == __middle)
+	std::__reverse(__middle, __last,   bidirectional_iterator_tag());
+      else
+	std::__reverse(__first,  __middle, bidirectional_iterator_tag());
+    }
+
+  /// This is a helper function for the rotate algorithm.
+  template<typename _RandomAccessIterator>
+    void
+    __rotate(_RandomAccessIterator __first,
+	     _RandomAccessIterator __middle,
+	     _RandomAccessIterator __last,
+	     random_access_iterator_tag)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_Mutable_RandomAccessIteratorConcept<
+				  _RandomAccessIterator>)
+
+      if (__first == __middle || __last  == __middle)
+	return;
+
+      typedef typename iterator_traits<_RandomAccessIterator>::difference_type
+	_Distance;
+      typedef typename iterator_traits<_RandomAccessIterator>::value_type
+	_ValueType;
+
+      _Distance __n = __last   - __first;
+      _Distance __k = __middle - __first;
+
+      if (__k == __n - __k)
+	{
+	  std::swap_ranges(__first, __middle, __middle);
+	  return;
+	}
+
+      _RandomAccessIterator __p = __first;
+
+      for (;;)
+	{
+	  if (__k < __n - __k)
+	    {
+	      if (__is_pod(_ValueType) && __k == 1)
+		{
+		  _ValueType __t = _GLIBCXX_MOVE(*__p);
+		  _GLIBCXX_MOVE3(__p + 1, __p + __n, __p);
+		  *(__p + __n - 1) = _GLIBCXX_MOVE(__t);
+		  return;
+		}
+	      _RandomAccessIterator __q = __p + __k;
+	      for (_Distance __i = 0; __i < __n - __k; ++ __i)
+		{
+		  std::iter_swap(__p, __q);
+		  ++__p;
+		  ++__q;
+		}
+	      __n %= __k;
+	      if (__n == 0)
+		return;
+	      std::swap(__n, __k);
+	      __k = __n - __k;
+	    }
+	  else
+	    {
+	      __k = __n - __k;
+	      if (__is_pod(_ValueType) && __k == 1)
+		{
+		  _ValueType __t = _GLIBCXX_MOVE(*(__p + __n - 1));
+		  _GLIBCXX_MOVE_BACKWARD3(__p, __p + __n - 1, __p + __n);
+		  *__p = _GLIBCXX_MOVE(__t);
+		  return;
+		}
+	      _RandomAccessIterator __q = __p + __n;
+	      __p = __q - __k;
+	      for (_Distance __i = 0; __i < __n - __k; ++ __i)
+		{
+		  --__p;
+		  --__q;
+		  std::iter_swap(__p, __q);
+		}
+	      __n %= __k;
+	      if (__n == 0)
+		return;
+	      std::swap(__n, __k);
+	    }
+	}
+    }
+
+  /**
+   *  @brief Rotate the elements of a sequence.
+   *  @ingroup mutating_algorithms
+   *  @param  __first   A forward iterator.
+   *  @param  __middle  A forward iterator.
+   *  @param  __last    A forward iterator.
+   *  @return  Nothing.
+   *
+   *  Rotates the elements of the range @p [__first,__last) by 
+   *  @p (__middle - __first) positions so that the element at @p __middle
+   *  is moved to @p __first, the element at @p __middle+1 is moved to
+   *  @p __first+1 and so on for each element in the range
+   *  @p [__first,__last).
+   *
+   *  This effectively swaps the ranges @p [__first,__middle) and
+   *  @p [__middle,__last).
+   *
+   *  Performs
+   *   @p *(__first+(n+(__last-__middle))%(__last-__first))=*(__first+n)
+   *  for each @p n in the range @p [0,__last-__first).
+  */
+  template<typename _ForwardIterator>
+    inline void
+    rotate(_ForwardIterator __first, _ForwardIterator __middle,
+	   _ForwardIterator __last)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_Mutable_ForwardIteratorConcept<
+				  _ForwardIterator>)
+      __glibcxx_requires_valid_range(__first, __middle);
+      __glibcxx_requires_valid_range(__middle, __last);
+
+      typedef typename iterator_traits<_ForwardIterator>::iterator_category
+	_IterType;
+      std::__rotate(__first, __middle, __last, _IterType());
+    }
+
+  /**
+   *  @brief Copy a sequence, rotating its elements.
+   *  @ingroup mutating_algorithms
+   *  @param  __first   A forward iterator.
+   *  @param  __middle  A forward iterator.
+   *  @param  __last    A forward iterator.
+   *  @param  __result  An output iterator.
+   *  @return   An iterator designating the end of the resulting sequence.
+   *
+   *  Copies the elements of the range @p [__first,__last) to the
+   *  range beginning at @result, rotating the copied elements by 
+   *  @p (__middle-__first) positions so that the element at @p __middle
+   *  is moved to @p __result, the element at @p __middle+1 is moved
+   *  to @p __result+1 and so on for each element in the range @p
+   *  [__first,__last).
+   *
+   *  Performs 
+   *  @p *(__result+(n+(__last-__middle))%(__last-__first))=*(__first+n)
+   *  for each @p n in the range @p [0,__last-__first).
+  */
+  template<typename _ForwardIterator, typename _OutputIterator>
+    _OutputIterator
+    rotate_copy(_ForwardIterator __first, _ForwardIterator __middle,
+                _ForwardIterator __last, _OutputIterator __result)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)
+      __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,
+		typename iterator_traits<_ForwardIterator>::value_type>)
+      __glibcxx_requires_valid_range(__first, __middle);
+      __glibcxx_requires_valid_range(__middle, __last);
+
+      return std::copy(__first, __middle,
+                       std::copy(__middle, __last, __result));
+    }
+
+  /// This is a helper function...
+  template<typename _ForwardIterator, typename _Predicate>
+    _ForwardIterator
+    __partition(_ForwardIterator __first, _ForwardIterator __last,
+		_Predicate __pred, forward_iterator_tag)
+    {
+      if (__first == __last)
+	return __first;
+
+      while (__pred(*__first))
+	if (++__first == __last)
+	  return __first;
+
+      _ForwardIterator __next = __first;
+
+      while (++__next != __last)
+	if (__pred(*__next))
+	  {
+	    std::iter_swap(__first, __next);
+	    ++__first;
+	  }
+
+      return __first;
+    }
+
+  /// This is a helper function...
+  template<typename _BidirectionalIterator, typename _Predicate>
+    _BidirectionalIterator
+    __partition(_BidirectionalIterator __first, _BidirectionalIterator __last,
+		_Predicate __pred, bidirectional_iterator_tag)
+    {
+      while (true)
+	{
+	  while (true)
+	    if (__first == __last)
+	      return __first;
+	    else if (__pred(*__first))
+	      ++__first;
+	    else
+	      break;
+	  --__last;
+	  while (true)
+	    if (__first == __last)
+	      return __first;
+	    else if (!bool(__pred(*__last)))
+	      --__last;
+	    else
+	      break;
+	  std::iter_swap(__first, __last);
+	  ++__first;
+	}
+    }
+
+  // partition
+
+  /// This is a helper function...
+  /// Requires __len != 0 and !__pred(*__first),
+  /// same as __stable_partition_adaptive.
+  template<typename _ForwardIterator, typename _Predicate, typename _Distance>
+    _ForwardIterator
+    __inplace_stable_partition(_ForwardIterator __first,
+			       _Predicate __pred, _Distance __len)
+    {
+      if (__len == 1)
+	return __first;
+      _ForwardIterator __middle = __first;
+      std::advance(__middle, __len / 2);
+      _ForwardIterator __left_split =
+	std::__inplace_stable_partition(__first, __pred, __len / 2);
+      // Advance past true-predicate values to satisfy this
+      // function's preconditions.
+      _Distance __right_len = __len - __len / 2;
+      _ForwardIterator __right_split =
+	std::__find_if_not_n(__middle, __right_len, __pred);
+      if (__right_len)
+	__right_split = std::__inplace_stable_partition(__middle,
+							__pred,
+							__right_len);
+      std::rotate(__left_split, __middle, __right_split);
+      std::advance(__left_split, std::distance(__middle, __right_split));
+      return __left_split;
+    }
+
+  /// This is a helper function...
+  /// Requires __first != __last and !__pred(*__first)
+  /// and __len == distance(__first, __last).
+  ///
+  /// !__pred(*__first) allows us to guarantee that we don't
+  /// move-assign an element onto itself.
+  template<typename _ForwardIterator, typename _Pointer, typename _Predicate,
+	   typename _Distance>
+    _ForwardIterator
+    __stable_partition_adaptive(_ForwardIterator __first,
+				_ForwardIterator __last,
+				_Predicate __pred, _Distance __len,
+				_Pointer __buffer,
+				_Distance __buffer_size)
+    {
+      if (__len <= __buffer_size)
+	{
+	  _ForwardIterator __result1 = __first;
+	  _Pointer __result2 = __buffer;
+	  // The precondition guarantees that !__pred(*__first), so
+	  // move that element to the buffer before starting the loop.
+	  // This ensures that we only call __pred once per element.
+	  *__result2 = _GLIBCXX_MOVE(*__first);
+	  ++__result2;
+	  ++__first;
+	  for (; __first != __last; ++__first)
+	    if (__pred(*__first))
+	      {
+		*__result1 = _GLIBCXX_MOVE(*__first);
+		++__result1;
+	      }
+	    else
+	      {
+		*__result2 = _GLIBCXX_MOVE(*__first);
+		++__result2;
+	      }
+	  _GLIBCXX_MOVE3(__buffer, __result2, __result1);
+	  return __result1;
+	}
+      else
+	{
+	  _ForwardIterator __middle = __first;
+	  std::advance(__middle, __len / 2);
+	  _ForwardIterator __left_split =
+	    std::__stable_partition_adaptive(__first, __middle, __pred,
+					     __len / 2, __buffer,
+					     __buffer_size);
+	  // Advance past true-predicate values to satisfy this
+	  // function's preconditions.
+	  _Distance __right_len = __len - __len / 2;
+	  _ForwardIterator __right_split =
+	    std::__find_if_not_n(__middle, __right_len, __pred);
+	  if (__right_len)
+	    __right_split =
+	      std::__stable_partition_adaptive(__right_split, __last, __pred,
+					       __right_len,
+					       __buffer, __buffer_size);
+	  std::rotate(__left_split, __middle, __right_split);
+	  std::advance(__left_split, std::distance(__middle, __right_split));
+	  return __left_split;
+	}
+    }
+
+  /**
+   *  @brief Move elements for which a predicate is true to the beginning
+   *         of a sequence, preserving relative ordering.
+   *  @ingroup mutating_algorithms
+   *  @param  __first   A forward iterator.
+   *  @param  __last    A forward iterator.
+   *  @param  __pred    A predicate functor.
+   *  @return  An iterator @p middle such that @p __pred(i) is true for each
+   *  iterator @p i in the range @p [first,middle) and false for each @p i
+   *  in the range @p [middle,last).
+   *
+   *  Performs the same function as @p partition() with the additional
+   *  guarantee that the relative ordering of elements in each group is
+   *  preserved, so any two elements @p x and @p y in the range
+   *  @p [__first,__last) such that @p __pred(x)==__pred(y) will have the same
+   *  relative ordering after calling @p stable_partition().
+  */
+  template<typename _ForwardIterator, typename _Predicate>
+    _ForwardIterator
+    stable_partition(_ForwardIterator __first, _ForwardIterator __last,
+		     _Predicate __pred)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_Mutable_ForwardIteratorConcept<
+				  _ForwardIterator>)
+      __glibcxx_function_requires(_UnaryPredicateConcept<_Predicate,
+	    typename iterator_traits<_ForwardIterator>::value_type>)
+      __glibcxx_requires_valid_range(__first, __last);
+
+      __first = std::__find_if_not(__first, __last, __pred);
+
+      if (__first == __last)
+	return __first;
+      else
+	{
+	  typedef typename iterator_traits<_ForwardIterator>::value_type
+	    _ValueType;
+	  typedef typename iterator_traits<_ForwardIterator>::difference_type
+	    _DistanceType;
+
+	  _Temporary_buffer<_ForwardIterator, _ValueType> __buf(__first,
+								__last);
+	if (__buf.size() > 0)
+	  return
+	    std::__stable_partition_adaptive(__first, __last, __pred,
+					  _DistanceType(__buf.requested_size()),
+					  __buf.begin(),
+					  _DistanceType(__buf.size()));
+	else
+	  return
+	    std::__inplace_stable_partition(__first, __pred,
+					 _DistanceType(__buf.requested_size()));
+	}
+    }
+
+  /// This is a helper function for the sort routines.
+  template<typename _RandomAccessIterator>
+    void
+    __heap_select(_RandomAccessIterator __first,
+		  _RandomAccessIterator __middle,
+		  _RandomAccessIterator __last)
+    {
+      std::make_heap(__first, __middle);
+      for (_RandomAccessIterator __i = __middle; __i < __last; ++__i)
+	if (*__i < *__first)
+	  std::__pop_heap(__first, __middle, __i);
+    }
+
+  /// This is a helper function for the sort routines.
+  template<typename _RandomAccessIterator, typename _Compare>
+    void
+    __heap_select(_RandomAccessIterator __first,
+		  _RandomAccessIterator __middle,
+		  _RandomAccessIterator __last, _Compare __comp)
+    {
+      std::make_heap(__first, __middle, __comp);
+      for (_RandomAccessIterator __i = __middle; __i < __last; ++__i)
+	if (__comp(*__i, *__first))
+	  std::__pop_heap(__first, __middle, __i, __comp);
+    }
+
+  // partial_sort
+
+  /**
+   *  @brief Copy the smallest elements of a sequence.
+   *  @ingroup sorting_algorithms
+   *  @param  __first   An iterator.
+   *  @param  __last    Another iterator.
+   *  @param  __result_first   A random-access iterator.
+   *  @param  __result_last    Another random-access iterator.
+   *  @return   An iterator indicating the end of the resulting sequence.
+   *
+   *  Copies and sorts the smallest N values from the range @p [__first,__last)
+   *  to the range beginning at @p __result_first, where the number of
+   *  elements to be copied, @p N, is the smaller of @p (__last-__first) and
+   *  @p (__result_last-__result_first).
+   *  After the sort if @e i and @e j are iterators in the range
+   *  @p [__result_first,__result_first+N) such that i precedes j then
+   *  *j<*i is false.
+   *  The value returned is @p __result_first+N.
+  */
+  template<typename _InputIterator, typename _RandomAccessIterator>
+    _RandomAccessIterator
+    partial_sort_copy(_InputIterator __first, _InputIterator __last,
+		      _RandomAccessIterator __result_first,
+		      _RandomAccessIterator __result_last)
+    {
+      typedef typename iterator_traits<_InputIterator>::value_type
+	_InputValueType;
+      typedef typename iterator_traits<_RandomAccessIterator>::value_type
+	_OutputValueType;
+      typedef typename iterator_traits<_RandomAccessIterator>::difference_type
+	_DistanceType;
+
+      // concept requirements
+      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)
+      __glibcxx_function_requires(_ConvertibleConcept<_InputValueType,
+				  _OutputValueType>)
+      __glibcxx_function_requires(_LessThanOpConcept<_InputValueType,
+				                     _OutputValueType>)
+      __glibcxx_function_requires(_LessThanComparableConcept<_OutputValueType>)
+      __glibcxx_requires_valid_range(__first, __last);
+      __glibcxx_requires_valid_range(__result_first, __result_last);
+
+      if (__result_first == __result_last)
+	return __result_last;
+      _RandomAccessIterator __result_real_last = __result_first;
+      while(__first != __last && __result_real_last != __result_last)
+	{
+	  *__result_real_last = *__first;
+	  ++__result_real_last;
+	  ++__first;
+	}
+      std::make_heap(__result_first, __result_real_last);
+      while (__first != __last)
+	{
+	  if (*__first < *__result_first)
+	    std::__adjust_heap(__result_first, _DistanceType(0),
+			       _DistanceType(__result_real_last
+					     - __result_first),
+			       _InputValueType(*__first));
+	  ++__first;
+	}
+      std::sort_heap(__result_first, __result_real_last);
+      return __result_real_last;
+    }
+
+  /**
+   *  @brief Copy the smallest elements of a sequence using a predicate for
+   *         comparison.
+   *  @ingroup sorting_algorithms
+   *  @param  __first   An input iterator.
+   *  @param  __last    Another input iterator.
+   *  @param  __result_first   A random-access iterator.
+   *  @param  __result_last    Another random-access iterator.
+   *  @param  __comp    A comparison functor.
+   *  @return   An iterator indicating the end of the resulting sequence.
+   *
+   *  Copies and sorts the smallest N values from the range @p [__first,__last)
+   *  to the range beginning at @p result_first, where the number of
+   *  elements to be copied, @p N, is the smaller of @p (__last-__first) and
+   *  @p (__result_last-__result_first).
+   *  After the sort if @e i and @e j are iterators in the range
+   *  @p [__result_first,__result_first+N) such that i precedes j then
+   *  @p __comp(*j,*i) is false.
+   *  The value returned is @p __result_first+N.
+  */
+  template<typename _InputIterator, typename _RandomAccessIterator, typename _Compare>
+    _RandomAccessIterator
+    partial_sort_copy(_InputIterator __first, _InputIterator __last,
+		      _RandomAccessIterator __result_first,
+		      _RandomAccessIterator __result_last,
+		      _Compare __comp)
+    {
+      typedef typename iterator_traits<_InputIterator>::value_type
+	_InputValueType;
+      typedef typename iterator_traits<_RandomAccessIterator>::value_type
+	_OutputValueType;
+      typedef typename iterator_traits<_RandomAccessIterator>::difference_type
+	_DistanceType;
+
+      // concept requirements
+      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)
+      __glibcxx_function_requires(_Mutable_RandomAccessIteratorConcept<
+				  _RandomAccessIterator>)
+      __glibcxx_function_requires(_ConvertibleConcept<_InputValueType,
+				  _OutputValueType>)
+      __glibcxx_function_requires(_BinaryPredicateConcept<_Compare,
+				  _InputValueType, _OutputValueType>)
+      __glibcxx_function_requires(_BinaryPredicateConcept<_Compare,
+				  _OutputValueType, _OutputValueType>)
+      __glibcxx_requires_valid_range(__first, __last);
+      __glibcxx_requires_valid_range(__result_first, __result_last);
+
+      if (__result_first == __result_last)
+	return __result_last;
+      _RandomAccessIterator __result_real_last = __result_first;
+      while(__first != __last && __result_real_last != __result_last)
+	{
+	  *__result_real_last = *__first;
+	  ++__result_real_last;
+	  ++__first;
+	}
+      std::make_heap(__result_first, __result_real_last, __comp);
+      while (__first != __last)
+	{
+	  if (__comp(*__first, *__result_first))
+	    std::__adjust_heap(__result_first, _DistanceType(0),
+			       _DistanceType(__result_real_last
+					     - __result_first),
+			       _InputValueType(*__first),
+			       __comp);
+	  ++__first;
+	}
+      std::sort_heap(__result_first, __result_real_last, __comp);
+      return __result_real_last;
+    }
+
+  /// This is a helper function for the sort routine.
+  template<typename _RandomAccessIterator>
+    void
+    __unguarded_linear_insert(_RandomAccessIterator __last)
+    {
+      typename iterator_traits<_RandomAccessIterator>::value_type
+	__val = _GLIBCXX_MOVE(*__last);
+      _RandomAccessIterator __next = __last;
+      --__next;
+      while (__val < *__next)
+	{
+	  *__last = _GLIBCXX_MOVE(*__next);
+	  __last = __next;
+	  --__next;
+	}
+      *__last = _GLIBCXX_MOVE(__val);
+    }
+
+  /// This is a helper function for the sort routine.
+  template<typename _RandomAccessIterator, typename _Compare>
+    void
+    __unguarded_linear_insert(_RandomAccessIterator __last,
+			      _Compare __comp)
+    {
+      typename iterator_traits<_RandomAccessIterator>::value_type
+	__val = _GLIBCXX_MOVE(*__last);
+      _RandomAccessIterator __next = __last;
+      --__next;
+      while (__comp(__val, *__next))
+	{
+	  *__last = _GLIBCXX_MOVE(*__next);
+	  __last = __next;
+	  --__next;
+	}
+      *__last = _GLIBCXX_MOVE(__val);
+    }
+
+  /// This is a helper function for the sort routine.
+  template<typename _RandomAccessIterator>
+    void
+    __insertion_sort(_RandomAccessIterator __first,
+		     _RandomAccessIterator __last)
+    {
+      if (__first == __last)
+	return;
+
+      for (_RandomAccessIterator __i = __first + 1; __i != __last; ++__i)
+	{
+	  if (*__i < *__first)
+	    {
+	      typename iterator_traits<_RandomAccessIterator>::value_type
+		__val = _GLIBCXX_MOVE(*__i);
+	      _GLIBCXX_MOVE_BACKWARD3(__first, __i, __i + 1);
+	      *__first = _GLIBCXX_MOVE(__val);
+	    }
+	  else
+	    std::__unguarded_linear_insert(__i);
+	}
+    }
+
+  /// This is a helper function for the sort routine.
+  template<typename _RandomAccessIterator, typename _Compare>
+    void
+    __insertion_sort(_RandomAccessIterator __first,
+		     _RandomAccessIterator __last, _Compare __comp)
+    {
+      if (__first == __last) return;
+
+      for (_RandomAccessIterator __i = __first + 1; __i != __last; ++__i)
+	{
+	  if (__comp(*__i, *__first))
+	    {
+	      typename iterator_traits<_RandomAccessIterator>::value_type
+		__val = _GLIBCXX_MOVE(*__i);
+	      _GLIBCXX_MOVE_BACKWARD3(__first, __i, __i + 1);
+	      *__first = _GLIBCXX_MOVE(__val);
+	    }
+	  else
+	    std::__unguarded_linear_insert(__i, __comp);
+	}
+    }
+
+  /// This is a helper function for the sort routine.
+  template<typename _RandomAccessIterator>
+    inline void
+    __unguarded_insertion_sort(_RandomAccessIterator __first,
+			       _RandomAccessIterator __last)
+    {
+      typedef typename iterator_traits<_RandomAccessIterator>::value_type
+	_ValueType;
+
+      for (_RandomAccessIterator __i = __first; __i != __last; ++__i)
+	std::__unguarded_linear_insert(__i);
+    }
+
+  /// This is a helper function for the sort routine.
+  template<typename _RandomAccessIterator, typename _Compare>
+    inline void
+    __unguarded_insertion_sort(_RandomAccessIterator __first,
+			       _RandomAccessIterator __last, _Compare __comp)
+    {
+      typedef typename iterator_traits<_RandomAccessIterator>::value_type
+	_ValueType;
+
+      for (_RandomAccessIterator __i = __first; __i != __last; ++__i)
+	std::__unguarded_linear_insert(__i, __comp);
+    }
+
+  /**
+   *  @doctodo
+   *  This controls some aspect of the sort routines.
+  */
+  enum { _S_threshold = 16 };
+
+  /// This is a helper function for the sort routine.
+  template<typename _RandomAccessIterator>
+    void
+    __final_insertion_sort(_RandomAccessIterator __first,
+			   _RandomAccessIterator __last)
+    {
+      if (__last - __first > int(_S_threshold))
+	{
+	  std::__insertion_sort(__first, __first + int(_S_threshold));
+	  std::__unguarded_insertion_sort(__first + int(_S_threshold), __last);
+	}
+      else
+	std::__insertion_sort(__first, __last);
+    }
+
+  /// This is a helper function for the sort routine.
+  template<typename _RandomAccessIterator, typename _Compare>
+    void
+    __final_insertion_sort(_RandomAccessIterator __first,
+			   _RandomAccessIterator __last, _Compare __comp)
+    {
+      if (__last - __first > int(_S_threshold))
+	{
+	  std::__insertion_sort(__first, __first + int(_S_threshold), __comp);
+	  std::__unguarded_insertion_sort(__first + int(_S_threshold), __last,
+					  __comp);
+	}
+      else
+	std::__insertion_sort(__first, __last, __comp);
+    }
+
+  /// This is a helper function...
+  template<typename _RandomAccessIterator, typename _Tp>
+    _RandomAccessIterator
+    __unguarded_partition(_RandomAccessIterator __first,
+			  _RandomAccessIterator __last, const _Tp& __pivot)
+    {
+      while (true)
+	{
+	  while (*__first < __pivot)
+	    ++__first;
+	  --__last;
+	  while (__pivot < *__last)
+	    --__last;
+	  if (!(__first < __last))
+	    return __first;
+	  std::iter_swap(__first, __last);
+	  ++__first;
+	}
+    }
+
+  /// This is a helper function...
+  template<typename _RandomAccessIterator, typename _Tp, typename _Compare>
+    _RandomAccessIterator
+    __unguarded_partition(_RandomAccessIterator __first,
+			  _RandomAccessIterator __last,
+			  const _Tp& __pivot, _Compare __comp)
+    {
+      while (true)
+	{
+	  while (__comp(*__first, __pivot))
+	    ++__first;
+	  --__last;
+	  while (__comp(__pivot, *__last))
+	    --__last;
+	  if (!(__first < __last))
+	    return __first;
+	  std::iter_swap(__first, __last);
+	  ++__first;
+	}
+    }
+
+  /// This is a helper function...
+  template<typename _RandomAccessIterator>
+    inline _RandomAccessIterator
+    __unguarded_partition_pivot(_RandomAccessIterator __first,
+				_RandomAccessIterator __last)
+    {
+      _RandomAccessIterator __mid = __first + (__last - __first) / 2;
+      std::__move_median_to_first(__first, __first + 1, __mid, __last - 1);
+      return std::__unguarded_partition(__first + 1, __last, *__first);
+    }
+
+
+  /// This is a helper function...
+  template<typename _RandomAccessIterator, typename _Compare>
+    inline _RandomAccessIterator
+    __unguarded_partition_pivot(_RandomAccessIterator __first,
+				_RandomAccessIterator __last, _Compare __comp)
+    {
+      _RandomAccessIterator __mid = __first + (__last - __first) / 2;
+      std::__move_median_to_first(__first, __first + 1, __mid, __last - 1,
+				  __comp);
+      return std::__unguarded_partition(__first + 1, __last, *__first, __comp);
+    }
+
+  /// This is a helper function for the sort routine.
+  template<typename _RandomAccessIterator, typename _Size>
+    void
+    __introsort_loop(_RandomAccessIterator __first,
+		     _RandomAccessIterator __last,
+		     _Size __depth_limit)
+    {
+      while (__last - __first > int(_S_threshold))
+	{
+	  if (__depth_limit == 0)
+	    {
+	      _GLIBCXX_STD_A::partial_sort(__first, __last, __last);
+	      return;
+	    }
+	  --__depth_limit;
+	  _RandomAccessIterator __cut =
+	    std::__unguarded_partition_pivot(__first, __last);
+	  std::__introsort_loop(__cut, __last, __depth_limit);
+	  __last = __cut;
+	}
+    }
+
+  /// This is a helper function for the sort routine.
+  template<typename _RandomAccessIterator, typename _Size, typename _Compare>
+    void
+    __introsort_loop(_RandomAccessIterator __first,
+		     _RandomAccessIterator __last,
+		     _Size __depth_limit, _Compare __comp)
+    {
+      while (__last - __first > int(_S_threshold))
+	{
+	  if (__depth_limit == 0)
+	    {
+	      _GLIBCXX_STD_A::partial_sort(__first, __last, __last, __comp);
+	      return;
+	    }
+	  --__depth_limit;
+	  _RandomAccessIterator __cut =
+	    std::__unguarded_partition_pivot(__first, __last, __comp);
+	  std::__introsort_loop(__cut, __last, __depth_limit, __comp);
+	  __last = __cut;
+	}
+    }
+
+  // sort
+
+  template<typename _RandomAccessIterator, typename _Size>
+    void
+    __introselect(_RandomAccessIterator __first, _RandomAccessIterator __nth,
+		  _RandomAccessIterator __last, _Size __depth_limit)
+    {
+      typedef typename iterator_traits<_RandomAccessIterator>::value_type
+	_ValueType;
+
+      while (__last - __first > 3)
+	{
+	  if (__depth_limit == 0)
+	    {
+	      std::__heap_select(__first, __nth + 1, __last);
+
+	      // Place the nth largest element in its final position.
+	      std::iter_swap(__first, __nth);
+	      return;
+	    }
+	  --__depth_limit;
+	  _RandomAccessIterator __cut =
+	    std::__unguarded_partition_pivot(__first, __last);
+	  if (__cut <= __nth)
+	    __first = __cut;
+	  else
+	    __last = __cut;
+	}
+      std::__insertion_sort(__first, __last);
+    }
+
+  template<typename _RandomAccessIterator, typename _Size, typename _Compare>
+    void
+    __introselect(_RandomAccessIterator __first, _RandomAccessIterator __nth,
+		  _RandomAccessIterator __last, _Size __depth_limit,
+		  _Compare __comp)
+    {
+      typedef typename iterator_traits<_RandomAccessIterator>::value_type
+	_ValueType;
+
+      while (__last - __first > 3)
+	{
+	  if (__depth_limit == 0)
+	    {
+	      std::__heap_select(__first, __nth + 1, __last, __comp);
+	      // Place the nth largest element in its final position.
+	      std::iter_swap(__first, __nth);
+	      return;
+	    }
+	  --__depth_limit;
+	  _RandomAccessIterator __cut =
+	    std::__unguarded_partition_pivot(__first, __last, __comp);
+	  if (__cut <= __nth)
+	    __first = __cut;
+	  else
+	    __last = __cut;
+	}
+      std::__insertion_sort(__first, __last, __comp);
+    }
+
+  // nth_element
+
+  // lower_bound moved to stl_algobase.h
+
+  /**
+   *  @brief Finds the first position in which @p __val could be inserted
+   *         without changing the ordering.
+   *  @ingroup binary_search_algorithms
+   *  @param  __first   An iterator.
+   *  @param  __last    Another iterator.
+   *  @param  __val     The search term.
+   *  @param  __comp    A functor to use for comparisons.
+   *  @return An iterator pointing to the first element <em>not less
+   *           than</em> @p __val, or end() if every element is less
+   *           than @p __val.
+   *  @ingroup binary_search_algorithms
+   *
+   *  The comparison function should have the same effects on ordering as
+   *  the function used for the initial sort.
+  */
+  template<typename _ForwardIterator, typename _Tp, typename _Compare>
+    _ForwardIterator
+    lower_bound(_ForwardIterator __first, _ForwardIterator __last,
+		const _Tp& __val, _Compare __comp)
+    {
+      typedef typename iterator_traits<_ForwardIterator>::value_type
+	_ValueType;
+      typedef typename iterator_traits<_ForwardIterator>::difference_type
+	_DistanceType;
+
+      // concept requirements
+      __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)
+      __glibcxx_function_requires(_BinaryPredicateConcept<_Compare,
+				  _ValueType, _Tp>)
+      __glibcxx_requires_partitioned_lower_pred(__first, __last,
+						__val, __comp);
+
+      _DistanceType __len = std::distance(__first, __last);
+
+      while (__len > 0)
+	{
+	  _DistanceType __half = __len >> 1;
+	  _ForwardIterator __middle = __first;
+	  std::advance(__middle, __half);
+	  if (__comp(*__middle, __val))
+	    {
+	      __first = __middle;
+	      ++__first;
+	      __len = __len - __half - 1;
+	    }
+	  else
+	    __len = __half;
+	}
+      return __first;
+    }
+
+  /**
+   *  @brief Finds the last position in which @p __val could be inserted
+   *         without changing the ordering.
+   *  @ingroup binary_search_algorithms
+   *  @param  __first   An iterator.
+   *  @param  __last    Another iterator.
+   *  @param  __val     The search term.
+   *  @return  An iterator pointing to the first element greater than @p __val,
+   *           or end() if no elements are greater than @p __val.
+   *  @ingroup binary_search_algorithms
+  */
+  template<typename _ForwardIterator, typename _Tp>
+    _ForwardIterator
+    upper_bound(_ForwardIterator __first, _ForwardIterator __last,
+		const _Tp& __val)
+    {
+      typedef typename iterator_traits<_ForwardIterator>::value_type
+	_ValueType;
+      typedef typename iterator_traits<_ForwardIterator>::difference_type
+	_DistanceType;
+
+      // concept requirements
+      __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)
+      __glibcxx_function_requires(_LessThanOpConcept<_Tp, _ValueType>)
+      __glibcxx_requires_partitioned_upper(__first, __last, __val);
+
+      _DistanceType __len = std::distance(__first, __last);
+
+      while (__len > 0)
+	{
+	  _DistanceType __half = __len >> 1;
+	  _ForwardIterator __middle = __first;
+	  std::advance(__middle, __half);
+	  if (__val < *__middle)
+	    __len = __half;
+	  else
+	    {
+	      __first = __middle;
+	      ++__first;
+	      __len = __len - __half - 1;
+	    }
+	}
+      return __first;
+    }
+
+  /**
+   *  @brief Finds the last position in which @p __val could be inserted
+   *         without changing the ordering.
+   *  @ingroup binary_search_algorithms
+   *  @param  __first   An iterator.
+   *  @param  __last    Another iterator.
+   *  @param  __val     The search term.
+   *  @param  __comp    A functor to use for comparisons.
+   *  @return  An iterator pointing to the first element greater than @p __val,
+   *           or end() if no elements are greater than @p __val.
+   *  @ingroup binary_search_algorithms
+   *
+   *  The comparison function should have the same effects on ordering as
+   *  the function used for the initial sort.
+  */
+  template<typename _ForwardIterator, typename _Tp, typename _Compare>
+    _ForwardIterator
+    upper_bound(_ForwardIterator __first, _ForwardIterator __last,
+		const _Tp& __val, _Compare __comp)
+    {
+      typedef typename iterator_traits<_ForwardIterator>::value_type
+	_ValueType;
+      typedef typename iterator_traits<_ForwardIterator>::difference_type
+	_DistanceType;
+
+      // concept requirements
+      __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)
+      __glibcxx_function_requires(_BinaryPredicateConcept<_Compare,
+				  _Tp, _ValueType>)
+      __glibcxx_requires_partitioned_upper_pred(__first, __last,
+						__val, __comp);
+
+      _DistanceType __len = std::distance(__first, __last);
+
+      while (__len > 0)
+	{
+	  _DistanceType __half = __len >> 1;
+	  _ForwardIterator __middle = __first;
+	  std::advance(__middle, __half);
+	  if (__comp(__val, *__middle))
+	    __len = __half;
+	  else
+	    {
+	      __first = __middle;
+	      ++__first;
+	      __len = __len - __half - 1;
+	    }
+	}
+      return __first;
+    }
+
+  /**
+   *  @brief Finds the largest subrange in which @p __val could be inserted
+   *         at any place in it without changing the ordering.
+   *  @ingroup binary_search_algorithms
+   *  @param  __first   An iterator.
+   *  @param  __last    Another iterator.
+   *  @param  __val     The search term.
+   *  @return  An pair of iterators defining the subrange.
+   *  @ingroup binary_search_algorithms
+   *
+   *  This is equivalent to
+   *  @code
+   *    std::make_pair(lower_bound(__first, __last, __val),
+   *                   upper_bound(__first, __last, __val))
+   *  @endcode
+   *  but does not actually call those functions.
+  */
+  template<typename _ForwardIterator, typename _Tp>
+    pair<_ForwardIterator, _ForwardIterator>
+    equal_range(_ForwardIterator __first, _ForwardIterator __last,
+		const _Tp& __val)
+    {
+      typedef typename iterator_traits<_ForwardIterator>::value_type
+	_ValueType;
+      typedef typename iterator_traits<_ForwardIterator>::difference_type
+	_DistanceType;
+
+      // concept requirements
+      __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)
+      __glibcxx_function_requires(_LessThanOpConcept<_ValueType, _Tp>)
+      __glibcxx_function_requires(_LessThanOpConcept<_Tp, _ValueType>)	
+      __glibcxx_requires_partitioned_lower(__first, __last, __val);
+      __glibcxx_requires_partitioned_upper(__first, __last, __val);      
+
+      _DistanceType __len = std::distance(__first, __last);
+ 
+      while (__len > 0)
+	{
+	  _DistanceType __half = __len >> 1;
+	  _ForwardIterator __middle = __first;
+	  std::advance(__middle, __half);
+	  if (*__middle < __val)
+	    {
+	      __first = __middle;
+	      ++__first;
+	      __len = __len - __half - 1;
+	    }
+	  else if (__val < *__middle)
+	    __len = __half;
+	  else
+	    {
+	      _ForwardIterator __left = std::lower_bound(__first, __middle,
+							 __val);
+	      std::advance(__first, __len);
+	      _ForwardIterator __right = std::upper_bound(++__middle, __first,
+							  __val);
+	      return pair<_ForwardIterator, _ForwardIterator>(__left, __right);
+	    }
+	}
+      return pair<_ForwardIterator, _ForwardIterator>(__first, __first);
+    }
+
+  /**
+   *  @brief Finds the largest subrange in which @p __val could be inserted
+   *         at any place in it without changing the ordering.
+   *  @param  __first   An iterator.
+   *  @param  __last    Another iterator.
+   *  @param  __val     The search term.
+   *  @param  __comp    A functor to use for comparisons.
+   *  @return  An pair of iterators defining the subrange.
+   *  @ingroup binary_search_algorithms
+   *
+   *  This is equivalent to
+   *  @code
+   *    std::make_pair(lower_bound(__first, __last, __val, __comp),
+   *                   upper_bound(__first, __last, __val, __comp))
+   *  @endcode
+   *  but does not actually call those functions.
+  */
+  template<typename _ForwardIterator, typename _Tp, typename _Compare>
+    pair<_ForwardIterator, _ForwardIterator>
+    equal_range(_ForwardIterator __first, _ForwardIterator __last,
+		const _Tp& __val, _Compare __comp)
+    {
+      typedef typename iterator_traits<_ForwardIterator>::value_type
+	_ValueType;
+      typedef typename iterator_traits<_ForwardIterator>::difference_type
+	_DistanceType;
+
+      // concept requirements
+      __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)
+      __glibcxx_function_requires(_BinaryPredicateConcept<_Compare,
+				  _ValueType, _Tp>)
+      __glibcxx_function_requires(_BinaryPredicateConcept<_Compare,
+				  _Tp, _ValueType>)
+      __glibcxx_requires_partitioned_lower_pred(__first, __last,
+						__val, __comp);
+      __glibcxx_requires_partitioned_upper_pred(__first, __last,
+						__val, __comp);
+
+      _DistanceType __len = std::distance(__first, __last);
+
+      while (__len > 0)
+	{
+	  _DistanceType __half = __len >> 1;
+	  _ForwardIterator __middle = __first;
+	  std::advance(__middle, __half);
+	  if (__comp(*__middle, __val))
+	    {
+	      __first = __middle;
+	      ++__first;
+	      __len = __len - __half - 1;
+	    }
+	  else if (__comp(__val, *__middle))
+	    __len = __half;
+	  else
+	    {
+	      _ForwardIterator __left = std::lower_bound(__first, __middle,
+							 __val, __comp);
+	      std::advance(__first, __len);
+	      _ForwardIterator __right = std::upper_bound(++__middle, __first,
+							  __val, __comp);
+	      return pair<_ForwardIterator, _ForwardIterator>(__left, __right);
+	    }
+	}
+      return pair<_ForwardIterator, _ForwardIterator>(__first, __first);
+    }
+
+  /**
+   *  @brief Determines whether an element exists in a range.
+   *  @ingroup binary_search_algorithms
+   *  @param  __first   An iterator.
+   *  @param  __last    Another iterator.
+   *  @param  __val     The search term.
+   *  @return True if @p __val (or its equivalent) is in [@p
+   *  __first,@p __last ].
+   *
+   *  Note that this does not actually return an iterator to @p __val.  For
+   *  that, use std::find or a container's specialized find member functions.
+  */
+  template<typename _ForwardIterator, typename _Tp>
+    bool
+    binary_search(_ForwardIterator __first, _ForwardIterator __last,
+                  const _Tp& __val)
+    {
+      typedef typename iterator_traits<_ForwardIterator>::value_type
+	_ValueType;
+
+      // concept requirements
+      __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)
+      __glibcxx_function_requires(_LessThanOpConcept<_Tp, _ValueType>)
+      __glibcxx_requires_partitioned_lower(__first, __last, __val);
+      __glibcxx_requires_partitioned_upper(__first, __last, __val);
+
+      _ForwardIterator __i = std::lower_bound(__first, __last, __val);
+      return __i != __last && !(__val < *__i);
+    }
+
+  /**
+   *  @brief Determines whether an element exists in a range.
+   *  @ingroup binary_search_algorithms
+   *  @param  __first   An iterator.
+   *  @param  __last    Another iterator.
+   *  @param  __val     The search term.
+   *  @param  __comp    A functor to use for comparisons.
+   *  @return  True if @p __val (or its equivalent) is in @p [__first,__last].
+   *
+   *  Note that this does not actually return an iterator to @p __val.  For
+   *  that, use std::find or a container's specialized find member functions.
+   *
+   *  The comparison function should have the same effects on ordering as
+   *  the function used for the initial sort.
+  */
+  template<typename _ForwardIterator, typename _Tp, typename _Compare>
+    bool
+    binary_search(_ForwardIterator __first, _ForwardIterator __last,
+                  const _Tp& __val, _Compare __comp)
+    {
+      typedef typename iterator_traits<_ForwardIterator>::value_type
+	_ValueType;
+
+      // concept requirements
+      __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)
+      __glibcxx_function_requires(_BinaryPredicateConcept<_Compare,
+				  _Tp, _ValueType>)
+      __glibcxx_requires_partitioned_lower_pred(__first, __last,
+						__val, __comp);
+      __glibcxx_requires_partitioned_upper_pred(__first, __last,
+						__val, __comp);
+
+      _ForwardIterator __i = std::lower_bound(__first, __last, __val, __comp);
+      return __i != __last && !bool(__comp(__val, *__i));
+    }
+
+  // merge
+
+  /// This is a helper function for the __merge_adaptive routines.
+  template<typename _InputIterator1, typename _InputIterator2,
+	   typename _OutputIterator>
+    void
+    __move_merge_adaptive(_InputIterator1 __first1, _InputIterator1 __last1,
+			  _InputIterator2 __first2, _InputIterator2 __last2,
+			  _OutputIterator __result)
+    {
+      while (__first1 != __last1 && __first2 != __last2)
+	{
+	  if (*__first2 < *__first1)
+	    {
+	      *__result = _GLIBCXX_MOVE(*__first2);
+	      ++__first2;
+	    }
+	  else
+	    {
+	      *__result = _GLIBCXX_MOVE(*__first1);
+	      ++__first1;
+	    }
+	  ++__result;
+	}
+      if (__first1 != __last1)
+	_GLIBCXX_MOVE3(__first1, __last1, __result);
+    }
+
+  /// This is a helper function for the __merge_adaptive routines.
+  template<typename _InputIterator1, typename _InputIterator2,
+	   typename _OutputIterator, typename _Compare>
+    void
+    __move_merge_adaptive(_InputIterator1 __first1, _InputIterator1 __last1,
+			  _InputIterator2 __first2, _InputIterator2 __last2,
+			  _OutputIterator __result, _Compare __comp)
+    {
+      while (__first1 != __last1 && __first2 != __last2)
+	{
+	  if (__comp(*__first2, *__first1))
+	    {
+	      *__result = _GLIBCXX_MOVE(*__first2);
+	      ++__first2;
+	    }
+	  else
+	    {
+	      *__result = _GLIBCXX_MOVE(*__first1);
+	      ++__first1;
+	    }
+	  ++__result;
+	}
+      if (__first1 != __last1)
+	_GLIBCXX_MOVE3(__first1, __last1, __result);
+    }
+
+  /// This is a helper function for the __merge_adaptive routines.
+  template<typename _BidirectionalIterator1, typename _BidirectionalIterator2,
+	   typename _BidirectionalIterator3>
+    void
+    __move_merge_adaptive_backward(_BidirectionalIterator1 __first1,
+				   _BidirectionalIterator1 __last1,
+				   _BidirectionalIterator2 __first2,
+				   _BidirectionalIterator2 __last2,
+				   _BidirectionalIterator3 __result)
+    {
+      if (__first1 == __last1)
+	{
+	  _GLIBCXX_MOVE_BACKWARD3(__first2, __last2, __result);
+	  return;
+	}
+      else if (__first2 == __last2)
+	return;
+
+      --__last1;
+      --__last2;
+      while (true)
+	{
+	  if (*__last2 < *__last1)
+	    {
+	      *--__result = _GLIBCXX_MOVE(*__last1);
+	      if (__first1 == __last1)
+		{
+		  _GLIBCXX_MOVE_BACKWARD3(__first2, ++__last2, __result);
+		  return;
+		}
+	      --__last1;
+	    }
+	  else
+	    {
+	      *--__result = _GLIBCXX_MOVE(*__last2);
+	      if (__first2 == __last2)
+		return;
+	      --__last2;
+	    }
+	}
+    }
+
+  /// This is a helper function for the __merge_adaptive routines.
+  template<typename _BidirectionalIterator1, typename _BidirectionalIterator2,
+	   typename _BidirectionalIterator3, typename _Compare>
+    void
+    __move_merge_adaptive_backward(_BidirectionalIterator1 __first1,
+				   _BidirectionalIterator1 __last1,
+				   _BidirectionalIterator2 __first2,
+				   _BidirectionalIterator2 __last2,
+				   _BidirectionalIterator3 __result,
+				   _Compare __comp)
+    {
+      if (__first1 == __last1)
+	{
+	  _GLIBCXX_MOVE_BACKWARD3(__first2, __last2, __result);
+	  return;
+	}
+      else if (__first2 == __last2)
+	return;
+
+      --__last1;
+      --__last2;
+      while (true)
+	{
+	  if (__comp(*__last2, *__last1))
+	    {
+	      *--__result = _GLIBCXX_MOVE(*__last1);
+	      if (__first1 == __last1)
+		{
+		  _GLIBCXX_MOVE_BACKWARD3(__first2, ++__last2, __result);
+		  return;
+		}
+	      --__last1;
+	    }
+	  else
+	    {
+	      *--__result = _GLIBCXX_MOVE(*__last2);
+	      if (__first2 == __last2)
+		return;
+	      --__last2;
+	    }
+	}
+    }
+
+  /// This is a helper function for the merge routines.
+  template<typename _BidirectionalIterator1, typename _BidirectionalIterator2,
+	   typename _Distance>
+    _BidirectionalIterator1
+    __rotate_adaptive(_BidirectionalIterator1 __first,
+		      _BidirectionalIterator1 __middle,
+		      _BidirectionalIterator1 __last,
+		      _Distance __len1, _Distance __len2,
+		      _BidirectionalIterator2 __buffer,
+		      _Distance __buffer_size)
+    {
+      _BidirectionalIterator2 __buffer_end;
+      if (__len1 > __len2 && __len2 <= __buffer_size)
+	{
+	  if (__len2)
+	    {
+	      __buffer_end = _GLIBCXX_MOVE3(__middle, __last, __buffer);
+	      _GLIBCXX_MOVE_BACKWARD3(__first, __middle, __last);
+	      return _GLIBCXX_MOVE3(__buffer, __buffer_end, __first);
+	    }
+	  else
+	    return __first;
+	}
+      else if (__len1 <= __buffer_size)
+	{
+	  if (__len1)
+	    {
+	      __buffer_end = _GLIBCXX_MOVE3(__first, __middle, __buffer);
+	      _GLIBCXX_MOVE3(__middle, __last, __first);
+	      return _GLIBCXX_MOVE_BACKWARD3(__buffer, __buffer_end, __last);
+	    }
+	  else
+	    return __last;
+	}
+      else
+	{
+	  std::rotate(__first, __middle, __last);
+	  std::advance(__first, std::distance(__middle, __last));
+	  return __first;
+	}
+    }
+
+  /// This is a helper function for the merge routines.
+  template<typename _BidirectionalIterator, typename _Distance,
+	   typename _Pointer>
+    void
+    __merge_adaptive(_BidirectionalIterator __first,
+                     _BidirectionalIterator __middle,
+		     _BidirectionalIterator __last,
+		     _Distance __len1, _Distance __len2,
+		     _Pointer __buffer, _Distance __buffer_size)
+    {
+      if (__len1 <= __len2 && __len1 <= __buffer_size)
+	{
+	  _Pointer __buffer_end = _GLIBCXX_MOVE3(__first, __middle, __buffer);
+	  std::__move_merge_adaptive(__buffer, __buffer_end, __middle, __last,
+				     __first);
+	}
+      else if (__len2 <= __buffer_size)
+	{
+	  _Pointer __buffer_end = _GLIBCXX_MOVE3(__middle, __last, __buffer);
+	  std::__move_merge_adaptive_backward(__first, __middle, __buffer,
+					      __buffer_end, __last);
+	}
+      else
+	{
+	  _BidirectionalIterator __first_cut = __first;
+	  _BidirectionalIterator __second_cut = __middle;
+	  _Distance __len11 = 0;
+	  _Distance __len22 = 0;
+	  if (__len1 > __len2)
+	    {
+	      __len11 = __len1 / 2;
+	      std::advance(__first_cut, __len11);
+	      __second_cut = std::lower_bound(__middle, __last,
+					      *__first_cut);
+	      __len22 = std::distance(__middle, __second_cut);
+	    }
+	  else
+	    {
+	      __len22 = __len2 / 2;
+	      std::advance(__second_cut, __len22);
+	      __first_cut = std::upper_bound(__first, __middle,
+					     *__second_cut);
+	      __len11 = std::distance(__first, __first_cut);
+	    }
+	  _BidirectionalIterator __new_middle =
+	    std::__rotate_adaptive(__first_cut, __middle, __second_cut,
+				   __len1 - __len11, __len22, __buffer,
+				   __buffer_size);
+	  std::__merge_adaptive(__first, __first_cut, __new_middle, __len11,
+				__len22, __buffer, __buffer_size);
+	  std::__merge_adaptive(__new_middle, __second_cut, __last,
+				__len1 - __len11,
+				__len2 - __len22, __buffer, __buffer_size);
+	}
+    }
+
+  /// This is a helper function for the merge routines.
+  template<typename _BidirectionalIterator, typename _Distance, 
+	   typename _Pointer, typename _Compare>
+    void
+    __merge_adaptive(_BidirectionalIterator __first,
+                     _BidirectionalIterator __middle,
+		     _BidirectionalIterator __last,
+		     _Distance __len1, _Distance __len2,
+		     _Pointer __buffer, _Distance __buffer_size,
+		     _Compare __comp)
+    {
+      if (__len1 <= __len2 && __len1 <= __buffer_size)
+	{
+	  _Pointer __buffer_end = _GLIBCXX_MOVE3(__first, __middle, __buffer);
+	  std::__move_merge_adaptive(__buffer, __buffer_end, __middle, __last,
+				     __first, __comp);
+	}
+      else if (__len2 <= __buffer_size)
+	{
+	  _Pointer __buffer_end = _GLIBCXX_MOVE3(__middle, __last, __buffer);
+	  std::__move_merge_adaptive_backward(__first, __middle, __buffer,
+					      __buffer_end, __last, __comp);
+	}
+      else
+	{
+	  _BidirectionalIterator __first_cut = __first;
+	  _BidirectionalIterator __second_cut = __middle;
+	  _Distance __len11 = 0;
+	  _Distance __len22 = 0;
+	  if (__len1 > __len2)
+	    {
+	      __len11 = __len1 / 2;
+	      std::advance(__first_cut, __len11);
+	      __second_cut = std::lower_bound(__middle, __last, *__first_cut,
+					      __comp);
+	      __len22 = std::distance(__middle, __second_cut);
+	    }
+	  else
+	    {
+	      __len22 = __len2 / 2;
+	      std::advance(__second_cut, __len22);
+	      __first_cut = std::upper_bound(__first, __middle, *__second_cut,
+					     __comp);
+	      __len11 = std::distance(__first, __first_cut);
+	    }
+	  _BidirectionalIterator __new_middle =
+	    std::__rotate_adaptive(__first_cut, __middle, __second_cut,
+				   __len1 - __len11, __len22, __buffer,
+				   __buffer_size);
+	  std::__merge_adaptive(__first, __first_cut, __new_middle, __len11,
+				__len22, __buffer, __buffer_size, __comp);
+	  std::__merge_adaptive(__new_middle, __second_cut, __last,
+				__len1 - __len11,
+				__len2 - __len22, __buffer,
+				__buffer_size, __comp);
+	}
+    }
+
+  /// This is a helper function for the merge routines.
+  template<typename _BidirectionalIterator, typename _Distance>
+    void
+    __merge_without_buffer(_BidirectionalIterator __first,
+			   _BidirectionalIterator __middle,
+			   _BidirectionalIterator __last,
+			   _Distance __len1, _Distance __len2)
+    {
+      if (__len1 == 0 || __len2 == 0)
+	return;
+      if (__len1 + __len2 == 2)
+	{
+	  if (*__middle < *__first)
+	    std::iter_swap(__first, __middle);
+	  return;
+	}
+      _BidirectionalIterator __first_cut = __first;
+      _BidirectionalIterator __second_cut = __middle;
+      _Distance __len11 = 0;
+      _Distance __len22 = 0;
+      if (__len1 > __len2)
+	{
+	  __len11 = __len1 / 2;
+	  std::advance(__first_cut, __len11);
+	  __second_cut = std::lower_bound(__middle, __last, *__first_cut);
+	  __len22 = std::distance(__middle, __second_cut);
+	}
+      else
+	{
+	  __len22 = __len2 / 2;
+	  std::advance(__second_cut, __len22);
+	  __first_cut = std::upper_bound(__first, __middle, *__second_cut);
+	  __len11 = std::distance(__first, __first_cut);
+	}
+      std::rotate(__first_cut, __middle, __second_cut);
+      _BidirectionalIterator __new_middle = __first_cut;
+      std::advance(__new_middle, std::distance(__middle, __second_cut));
+      std::__merge_without_buffer(__first, __first_cut, __new_middle,
+				  __len11, __len22);
+      std::__merge_without_buffer(__new_middle, __second_cut, __last,
+				  __len1 - __len11, __len2 - __len22);
+    }
+
+  /// This is a helper function for the merge routines.
+  template<typename _BidirectionalIterator, typename _Distance,
+	   typename _Compare>
+    void
+    __merge_without_buffer(_BidirectionalIterator __first,
+                           _BidirectionalIterator __middle,
+			   _BidirectionalIterator __last,
+			   _Distance __len1, _Distance __len2,
+			   _Compare __comp)
+    {
+      if (__len1 == 0 || __len2 == 0)
+	return;
+      if (__len1 + __len2 == 2)
+	{
+	  if (__comp(*__middle, *__first))
+	    std::iter_swap(__first, __middle);
+	  return;
+	}
+      _BidirectionalIterator __first_cut = __first;
+      _BidirectionalIterator __second_cut = __middle;
+      _Distance __len11 = 0;
+      _Distance __len22 = 0;
+      if (__len1 > __len2)
+	{
+	  __len11 = __len1 / 2;
+	  std::advance(__first_cut, __len11);
+	  __second_cut = std::lower_bound(__middle, __last, *__first_cut,
+					  __comp);
+	  __len22 = std::distance(__middle, __second_cut);
+	}
+      else
+	{
+	  __len22 = __len2 / 2;
+	  std::advance(__second_cut, __len22);
+	  __first_cut = std::upper_bound(__first, __middle, *__second_cut,
+					 __comp);
+	  __len11 = std::distance(__first, __first_cut);
+	}
+      std::rotate(__first_cut, __middle, __second_cut);
+      _BidirectionalIterator __new_middle = __first_cut;
+      std::advance(__new_middle, std::distance(__middle, __second_cut));
+      std::__merge_without_buffer(__first, __first_cut, __new_middle,
+				  __len11, __len22, __comp);
+      std::__merge_without_buffer(__new_middle, __second_cut, __last,
+				  __len1 - __len11, __len2 - __len22, __comp);
+    }
+
+  /**
+   *  @brief Merges two sorted ranges in place.
+   *  @ingroup sorting_algorithms
+   *  @param  __first   An iterator.
+   *  @param  __middle  Another iterator.
+   *  @param  __last    Another iterator.
+   *  @return  Nothing.
+   *
+   *  Merges two sorted and consecutive ranges, [__first,__middle) and
+   *  [__middle,__last), and puts the result in [__first,__last).  The
+   *  output will be sorted.  The sort is @e stable, that is, for
+   *  equivalent elements in the two ranges, elements from the first
+   *  range will always come before elements from the second.
+   *
+   *  If enough additional memory is available, this takes (__last-__first)-1
+   *  comparisons.  Otherwise an NlogN algorithm is used, where N is
+   *  distance(__first,__last).
+  */
+  template<typename _BidirectionalIterator>
+    void
+    inplace_merge(_BidirectionalIterator __first,
+		  _BidirectionalIterator __middle,
+		  _BidirectionalIterator __last)
+    {
+      typedef typename iterator_traits<_BidirectionalIterator>::value_type
+          _ValueType;
+      typedef typename iterator_traits<_BidirectionalIterator>::difference_type
+          _DistanceType;
+
+      // concept requirements
+      __glibcxx_function_requires(_Mutable_BidirectionalIteratorConcept<
+	    _BidirectionalIterator>)
+      __glibcxx_function_requires(_LessThanComparableConcept<_ValueType>)
+      __glibcxx_requires_sorted(__first, __middle);
+      __glibcxx_requires_sorted(__middle, __last);
+
+      if (__first == __middle || __middle == __last)
+	return;
+
+      _DistanceType __len1 = std::distance(__first, __middle);
+      _DistanceType __len2 = std::distance(__middle, __last);
+
+      _Temporary_buffer<_BidirectionalIterator, _ValueType> __buf(__first,
+								  __last);
+      if (__buf.begin() == 0)
+	std::__merge_without_buffer(__first, __middle, __last, __len1, __len2);
+      else
+	std::__merge_adaptive(__first, __middle, __last, __len1, __len2,
+			      __buf.begin(), _DistanceType(__buf.size()));
+    }
+
+  /**
+   *  @brief Merges two sorted ranges in place.
+   *  @ingroup sorting_algorithms
+   *  @param  __first   An iterator.
+   *  @param  __middle  Another iterator.
+   *  @param  __last    Another iterator.
+   *  @param  __comp    A functor to use for comparisons.
+   *  @return  Nothing.
+   *
+   *  Merges two sorted and consecutive ranges, [__first,__middle) and
+   *  [middle,last), and puts the result in [__first,__last).  The output will
+   *  be sorted.  The sort is @e stable, that is, for equivalent
+   *  elements in the two ranges, elements from the first range will always
+   *  come before elements from the second.
+   *
+   *  If enough additional memory is available, this takes (__last-__first)-1
+   *  comparisons.  Otherwise an NlogN algorithm is used, where N is
+   *  distance(__first,__last).
+   *
+   *  The comparison function should have the same effects on ordering as
+   *  the function used for the initial sort.
+  */
+  template<typename _BidirectionalIterator, typename _Compare>
+    void
+    inplace_merge(_BidirectionalIterator __first,
+		  _BidirectionalIterator __middle,
+		  _BidirectionalIterator __last,
+		  _Compare __comp)
+    {
+      typedef typename iterator_traits<_BidirectionalIterator>::value_type
+          _ValueType;
+      typedef typename iterator_traits<_BidirectionalIterator>::difference_type
+          _DistanceType;
+
+      // concept requirements
+      __glibcxx_function_requires(_Mutable_BidirectionalIteratorConcept<
+	    _BidirectionalIterator>)
+      __glibcxx_function_requires(_BinaryPredicateConcept<_Compare,
+	    _ValueType, _ValueType>)
+      __glibcxx_requires_sorted_pred(__first, __middle, __comp);
+      __glibcxx_requires_sorted_pred(__middle, __last, __comp);
+
+      if (__first == __middle || __middle == __last)
+	return;
+
+      const _DistanceType __len1 = std::distance(__first, __middle);
+      const _DistanceType __len2 = std::distance(__middle, __last);
+
+      _Temporary_buffer<_BidirectionalIterator, _ValueType> __buf(__first,
+								  __last);
+      if (__buf.begin() == 0)
+	std::__merge_without_buffer(__first, __middle, __last, __len1,
+				    __len2, __comp);
+      else
+	std::__merge_adaptive(__first, __middle, __last, __len1, __len2,
+			      __buf.begin(), _DistanceType(__buf.size()),
+			      __comp);
+    }
+
+
+  /// This is a helper function for the __merge_sort_loop routines.
+  template<typename _InputIterator1, typename _InputIterator2,
+	   typename _OutputIterator>
+    _OutputIterator
+    __move_merge(_InputIterator1 __first1, _InputIterator1 __last1,
+		 _InputIterator2 __first2, _InputIterator2 __last2,
+		 _OutputIterator __result)
+    {
+      while (__first1 != __last1 && __first2 != __last2)
+	{
+	  if (*__first2 < *__first1)
+	    {
+	      *__result = _GLIBCXX_MOVE(*__first2);
+	      ++__first2;
+	    }
+	  else
+	    {
+	      *__result = _GLIBCXX_MOVE(*__first1);
+	      ++__first1;
+	    }
+	  ++__result;
+	}
+      return _GLIBCXX_MOVE3(__first2, __last2,
+			    _GLIBCXX_MOVE3(__first1, __last1,
+					   __result));
+    }
+
+  /// This is a helper function for the __merge_sort_loop routines.
+  template<typename _InputIterator1, typename _InputIterator2,
+	   typename _OutputIterator, typename _Compare>
+    _OutputIterator
+    __move_merge(_InputIterator1 __first1, _InputIterator1 __last1,
+		 _InputIterator2 __first2, _InputIterator2 __last2,
+		 _OutputIterator __result, _Compare __comp)
+    {
+      while (__first1 != __last1 && __first2 != __last2)
+	{
+	  if (__comp(*__first2, *__first1))
+	    {
+	      *__result = _GLIBCXX_MOVE(*__first2);
+	      ++__first2;
+	    }
+	  else
+	    {
+	      *__result = _GLIBCXX_MOVE(*__first1);
+	      ++__first1;
+	    }
+	  ++__result;
+	}
+      return _GLIBCXX_MOVE3(__first2, __last2,
+			    _GLIBCXX_MOVE3(__first1, __last1,
+					   __result));
+    }
+
+  template<typename _RandomAccessIterator1, typename _RandomAccessIterator2,
+	   typename _Distance>
+    void
+    __merge_sort_loop(_RandomAccessIterator1 __first,
+		      _RandomAccessIterator1 __last,
+		      _RandomAccessIterator2 __result,
+		      _Distance __step_size)
+    {
+      const _Distance __two_step = 2 * __step_size;
+
+      while (__last - __first >= __two_step)
+	{
+	  __result = std::__move_merge(__first, __first + __step_size,
+				       __first + __step_size,
+				       __first + __two_step, __result);
+	  __first += __two_step;
+	}
+
+      __step_size = std::min(_Distance(__last - __first), __step_size);
+      std::__move_merge(__first, __first + __step_size,
+			__first + __step_size, __last, __result);
+    }
+
+  template<typename _RandomAccessIterator1, typename _RandomAccessIterator2,
+	   typename _Distance, typename _Compare>
+    void
+    __merge_sort_loop(_RandomAccessIterator1 __first,
+		      _RandomAccessIterator1 __last,
+		      _RandomAccessIterator2 __result, _Distance __step_size,
+		      _Compare __comp)
+    {
+      const _Distance __two_step = 2 * __step_size;
+
+      while (__last - __first >= __two_step)
+	{
+	  __result = std::__move_merge(__first, __first + __step_size,
+				       __first + __step_size,
+				       __first + __two_step,
+				       __result, __comp);
+	  __first += __two_step;
+	}
+      __step_size = std::min(_Distance(__last - __first), __step_size);
+
+      std::__move_merge(__first,__first + __step_size,
+			__first + __step_size, __last, __result, __comp);
+    }
+
+  template<typename _RandomAccessIterator, typename _Distance>
+    void
+    __chunk_insertion_sort(_RandomAccessIterator __first,
+			   _RandomAccessIterator __last,
+			   _Distance __chunk_size)
+    {
+      while (__last - __first >= __chunk_size)
+	{
+	  std::__insertion_sort(__first, __first + __chunk_size);
+	  __first += __chunk_size;
+	}
+      std::__insertion_sort(__first, __last);
+    }
+
+  template<typename _RandomAccessIterator, typename _Distance,
+	   typename _Compare>
+    void
+    __chunk_insertion_sort(_RandomAccessIterator __first,
+			   _RandomAccessIterator __last,
+			   _Distance __chunk_size, _Compare __comp)
+    {
+      while (__last - __first >= __chunk_size)
+	{
+	  std::__insertion_sort(__first, __first + __chunk_size, __comp);
+	  __first += __chunk_size;
+	}
+      std::__insertion_sort(__first, __last, __comp);
+    }
+
+  enum { _S_chunk_size = 7 };
+
+  template<typename _RandomAccessIterator, typename _Pointer>
+    void
+    __merge_sort_with_buffer(_RandomAccessIterator __first,
+			     _RandomAccessIterator __last,
+                             _Pointer __buffer)
+    {
+      typedef typename iterator_traits<_RandomAccessIterator>::difference_type
+	_Distance;
+
+      const _Distance __len = __last - __first;
+      const _Pointer __buffer_last = __buffer + __len;
+
+      _Distance __step_size = _S_chunk_size;
+      std::__chunk_insertion_sort(__first, __last, __step_size);
+
+      while (__step_size < __len)
+	{
+	  std::__merge_sort_loop(__first, __last, __buffer, __step_size);
+	  __step_size *= 2;
+	  std::__merge_sort_loop(__buffer, __buffer_last, __first, __step_size);
+	  __step_size *= 2;
+	}
+    }
+
+  template<typename _RandomAccessIterator, typename _Pointer, typename _Compare>
+    void
+    __merge_sort_with_buffer(_RandomAccessIterator __first,
+			     _RandomAccessIterator __last,
+                             _Pointer __buffer, _Compare __comp)
+    {
+      typedef typename iterator_traits<_RandomAccessIterator>::difference_type
+	_Distance;
+
+      const _Distance __len = __last - __first;
+      const _Pointer __buffer_last = __buffer + __len;
+
+      _Distance __step_size = _S_chunk_size;
+      std::__chunk_insertion_sort(__first, __last, __step_size, __comp);
+
+      while (__step_size < __len)
+	{
+	  std::__merge_sort_loop(__first, __last, __buffer,
+				 __step_size, __comp);
+	  __step_size *= 2;
+	  std::__merge_sort_loop(__buffer, __buffer_last, __first,
+				 __step_size, __comp);
+	  __step_size *= 2;
+	}
+    }
+
+  template<typename _RandomAccessIterator, typename _Pointer,
+	   typename _Distance>
+    void
+    __stable_sort_adaptive(_RandomAccessIterator __first,
+			   _RandomAccessIterator __last,
+                           _Pointer __buffer, _Distance __buffer_size)
+    {
+      const _Distance __len = (__last - __first + 1) / 2;
+      const _RandomAccessIterator __middle = __first + __len;
+      if (__len > __buffer_size)
+	{
+	  std::__stable_sort_adaptive(__first, __middle,
+				      __buffer, __buffer_size);
+	  std::__stable_sort_adaptive(__middle, __last,
+				      __buffer, __buffer_size);
+	}
+      else
+	{
+	  std::__merge_sort_with_buffer(__first, __middle, __buffer);
+	  std::__merge_sort_with_buffer(__middle, __last, __buffer);
+	}
+      std::__merge_adaptive(__first, __middle, __last,
+			    _Distance(__middle - __first),
+			    _Distance(__last - __middle),
+			    __buffer, __buffer_size);
+    }
+
+  template<typename _RandomAccessIterator, typename _Pointer,
+	   typename _Distance, typename _Compare>
+    void
+    __stable_sort_adaptive(_RandomAccessIterator __first,
+			   _RandomAccessIterator __last,
+                           _Pointer __buffer, _Distance __buffer_size,
+                           _Compare __comp)
+    {
+      const _Distance __len = (__last - __first + 1) / 2;
+      const _RandomAccessIterator __middle = __first + __len;
+      if (__len > __buffer_size)
+	{
+	  std::__stable_sort_adaptive(__first, __middle, __buffer,
+				      __buffer_size, __comp);
+	  std::__stable_sort_adaptive(__middle, __last, __buffer,
+				      __buffer_size, __comp);
+	}
+      else
+	{
+	  std::__merge_sort_with_buffer(__first, __middle, __buffer, __comp);
+	  std::__merge_sort_with_buffer(__middle, __last, __buffer, __comp);
+	}
+      std::__merge_adaptive(__first, __middle, __last,
+			    _Distance(__middle - __first),
+			    _Distance(__last - __middle),
+			    __buffer, __buffer_size,
+			    __comp);
+    }
+
+  /// This is a helper function for the stable sorting routines.
+  template<typename _RandomAccessIterator>
+    void
+    __inplace_stable_sort(_RandomAccessIterator __first,
+			  _RandomAccessIterator __last)
+    {
+      if (__last - __first < 15)
+	{
+	  std::__insertion_sort(__first, __last);
+	  return;
+	}
+      _RandomAccessIterator __middle = __first + (__last - __first) / 2;
+      std::__inplace_stable_sort(__first, __middle);
+      std::__inplace_stable_sort(__middle, __last);
+      std::__merge_without_buffer(__first, __middle, __last,
+				  __middle - __first,
+				  __last - __middle);
+    }
+
+  /// This is a helper function for the stable sorting routines.
+  template<typename _RandomAccessIterator, typename _Compare>
+    void
+    __inplace_stable_sort(_RandomAccessIterator __first,
+			  _RandomAccessIterator __last, _Compare __comp)
+    {
+      if (__last - __first < 15)
+	{
+	  std::__insertion_sort(__first, __last, __comp);
+	  return;
+	}
+      _RandomAccessIterator __middle = __first + (__last - __first) / 2;
+      std::__inplace_stable_sort(__first, __middle, __comp);
+      std::__inplace_stable_sort(__middle, __last, __comp);
+      std::__merge_without_buffer(__first, __middle, __last,
+				  __middle - __first,
+				  __last - __middle,
+				  __comp);
+    }
+
+  // stable_sort
+
+  // Set algorithms: includes, set_union, set_intersection, set_difference,
+  // set_symmetric_difference.  All of these algorithms have the precondition
+  // that their input ranges are sorted and the postcondition that their output
+  // ranges are sorted.
+
+  /**
+   *  @brief Determines whether all elements of a sequence exists in a range.
+   *  @param  __first1  Start of search range.
+   *  @param  __last1   End of search range.
+   *  @param  __first2  Start of sequence
+   *  @param  __last2   End of sequence.
+   *  @return  True if each element in [__first2,__last2) is contained in order
+   *  within [__first1,__last1).  False otherwise.
+   *  @ingroup set_algorithms
+   *
+   *  This operation expects both [__first1,__last1) and
+   *  [__first2,__last2) to be sorted.  Searches for the presence of
+   *  each element in [__first2,__last2) within [__first1,__last1).
+   *  The iterators over each range only move forward, so this is a
+   *  linear algorithm.  If an element in [__first2,__last2) is not
+   *  found before the search iterator reaches @p __last2, false is
+   *  returned.
+  */
+  template<typename _InputIterator1, typename _InputIterator2>
+    bool
+    includes(_InputIterator1 __first1, _InputIterator1 __last1,
+	     _InputIterator2 __first2, _InputIterator2 __last2)
+    {
+      typedef typename iterator_traits<_InputIterator1>::value_type
+	_ValueType1;
+      typedef typename iterator_traits<_InputIterator2>::value_type
+	_ValueType2;
+
+      // concept requirements
+      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator1>)
+      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator2>)
+      __glibcxx_function_requires(_LessThanOpConcept<_ValueType1, _ValueType2>)
+      __glibcxx_function_requires(_LessThanOpConcept<_ValueType2, _ValueType1>)
+      __glibcxx_requires_sorted_set(__first1, __last1, __first2);
+      __glibcxx_requires_sorted_set(__first2, __last2, __first1);
+
+      while (__first1 != __last1 && __first2 != __last2)
+	if (*__first2 < *__first1)
+	  return false;
+	else if(*__first1 < *__first2)
+	  ++__first1;
+	else
+	  ++__first1, ++__first2;
+
+      return __first2 == __last2;
+    }
+
+  /**
+   *  @brief Determines whether all elements of a sequence exists in a range
+   *  using comparison.
+   *  @ingroup set_algorithms
+   *  @param  __first1  Start of search range.
+   *  @param  __last1   End of search range.
+   *  @param  __first2  Start of sequence
+   *  @param  __last2   End of sequence.
+   *  @param  __comp    Comparison function to use.
+   *  @return True if each element in [__first2,__last2) is contained
+   *  in order within [__first1,__last1) according to comp.  False
+   *  otherwise.  @ingroup set_algorithms
+   *
+   *  This operation expects both [__first1,__last1) and
+   *  [__first2,__last2) to be sorted.  Searches for the presence of
+   *  each element in [__first2,__last2) within [__first1,__last1),
+   *  using comp to decide.  The iterators over each range only move
+   *  forward, so this is a linear algorithm.  If an element in
+   *  [__first2,__last2) is not found before the search iterator
+   *  reaches @p __last2, false is returned.
+  */
+  template<typename _InputIterator1, typename _InputIterator2,
+	   typename _Compare>
+    bool
+    includes(_InputIterator1 __first1, _InputIterator1 __last1,
+	     _InputIterator2 __first2, _InputIterator2 __last2,
+	     _Compare __comp)
+    {
+      typedef typename iterator_traits<_InputIterator1>::value_type
+	_ValueType1;
+      typedef typename iterator_traits<_InputIterator2>::value_type
+	_ValueType2;
+
+      // concept requirements
+      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator1>)
+      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator2>)
+      __glibcxx_function_requires(_BinaryPredicateConcept<_Compare,
+				  _ValueType1, _ValueType2>)
+      __glibcxx_function_requires(_BinaryPredicateConcept<_Compare,
+				  _ValueType2, _ValueType1>)
+      __glibcxx_requires_sorted_set_pred(__first1, __last1, __first2, __comp);
+      __glibcxx_requires_sorted_set_pred(__first2, __last2, __first1, __comp);
+
+      while (__first1 != __last1 && __first2 != __last2)
+	if (__comp(*__first2, *__first1))
+	  return false;
+	else if(__comp(*__first1, *__first2))
+	  ++__first1;
+	else
+	  ++__first1, ++__first2;
+
+      return __first2 == __last2;
+    }
+
+  // nth_element
+  // merge
+  // set_difference
+  // set_intersection
+  // set_union
+  // stable_sort
+  // set_symmetric_difference
+  // min_element
+  // max_element
+
+  /**
+   *  @brief  Permute range into the next @e dictionary ordering.
+   *  @ingroup sorting_algorithms
+   *  @param  __first  Start of range.
+   *  @param  __last   End of range.
+   *  @return  False if wrapped to first permutation, true otherwise.
+   *
+   *  Treats all permutations of the range as a set of @e dictionary sorted
+   *  sequences.  Permutes the current sequence into the next one of this set.
+   *  Returns true if there are more sequences to generate.  If the sequence
+   *  is the largest of the set, the smallest is generated and false returned.
+  */
+  template<typename _BidirectionalIterator>
+    bool
+    next_permutation(_BidirectionalIterator __first,
+		     _BidirectionalIterator __last)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_BidirectionalIteratorConcept<
+				  _BidirectionalIterator>)
+      __glibcxx_function_requires(_LessThanComparableConcept<
+	    typename iterator_traits<_BidirectionalIterator>::value_type>)
+      __glibcxx_requires_valid_range(__first, __last);
+
+      if (__first == __last)
+	return false;
+      _BidirectionalIterator __i = __first;
+      ++__i;
+      if (__i == __last)
+	return false;
+      __i = __last;
+      --__i;
+
+      for(;;)
+	{
+	  _BidirectionalIterator __ii = __i;
+	  --__i;
+	  if (*__i < *__ii)
+	    {
+	      _BidirectionalIterator __j = __last;
+	      while (!(*__i < *--__j))
+		{}
+	      std::iter_swap(__i, __j);
+	      std::reverse(__ii, __last);
+	      return true;
+	    }
+	  if (__i == __first)
+	    {
+	      std::reverse(__first, __last);
+	      return false;
+	    }
+	}
+    }
+
+  /**
+   *  @brief  Permute range into the next @e dictionary ordering using
+   *          comparison functor.
+   *  @ingroup sorting_algorithms
+   *  @param  __first  Start of range.
+   *  @param  __last   End of range.
+   *  @param  __comp   A comparison functor.
+   *  @return  False if wrapped to first permutation, true otherwise.
+   *
+   *  Treats all permutations of the range [__first,__last) as a set of
+   *  @e dictionary sorted sequences ordered by @p __comp.  Permutes the current
+   *  sequence into the next one of this set.  Returns true if there are more
+   *  sequences to generate.  If the sequence is the largest of the set, the
+   *  smallest is generated and false returned.
+  */
+  template<typename _BidirectionalIterator, typename _Compare>
+    bool
+    next_permutation(_BidirectionalIterator __first,
+		     _BidirectionalIterator __last, _Compare __comp)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_BidirectionalIteratorConcept<
+				  _BidirectionalIterator>)
+      __glibcxx_function_requires(_BinaryPredicateConcept<_Compare,
+	    typename iterator_traits<_BidirectionalIterator>::value_type,
+	    typename iterator_traits<_BidirectionalIterator>::value_type>)
+      __glibcxx_requires_valid_range(__first, __last);
+
+      if (__first == __last)
+	return false;
+      _BidirectionalIterator __i = __first;
+      ++__i;
+      if (__i == __last)
+	return false;
+      __i = __last;
+      --__i;
+
+      for(;;)
+	{
+	  _BidirectionalIterator __ii = __i;
+	  --__i;
+	  if (__comp(*__i, *__ii))
+	    {
+	      _BidirectionalIterator __j = __last;
+	      while (!bool(__comp(*__i, *--__j)))
+		{}
+	      std::iter_swap(__i, __j);
+	      std::reverse(__ii, __last);
+	      return true;
+	    }
+	  if (__i == __first)
+	    {
+	      std::reverse(__first, __last);
+	      return false;
+	    }
+	}
+    }
+
+  /**
+   *  @brief  Permute range into the previous @e dictionary ordering.
+   *  @ingroup sorting_algorithms
+   *  @param  __first  Start of range.
+   *  @param  __last   End of range.
+   *  @return  False if wrapped to last permutation, true otherwise.
+   *
+   *  Treats all permutations of the range as a set of @e dictionary sorted
+   *  sequences.  Permutes the current sequence into the previous one of this
+   *  set.  Returns true if there are more sequences to generate.  If the
+   *  sequence is the smallest of the set, the largest is generated and false
+   *  returned.
+  */
+  template<typename _BidirectionalIterator>
+    bool
+    prev_permutation(_BidirectionalIterator __first,
+		     _BidirectionalIterator __last)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_BidirectionalIteratorConcept<
+				  _BidirectionalIterator>)
+      __glibcxx_function_requires(_LessThanComparableConcept<
+	    typename iterator_traits<_BidirectionalIterator>::value_type>)
+      __glibcxx_requires_valid_range(__first, __last);
+
+      if (__first == __last)
+	return false;
+      _BidirectionalIterator __i = __first;
+      ++__i;
+      if (__i == __last)
+	return false;
+      __i = __last;
+      --__i;
+
+      for(;;)
+	{
+	  _BidirectionalIterator __ii = __i;
+	  --__i;
+	  if (*__ii < *__i)
+	    {
+	      _BidirectionalIterator __j = __last;
+	      while (!(*--__j < *__i))
+		{}
+	      std::iter_swap(__i, __j);
+	      std::reverse(__ii, __last);
+	      return true;
+	    }
+	  if (__i == __first)
+	    {
+	      std::reverse(__first, __last);
+	      return false;
+	    }
+	}
+    }
+
+  /**
+   *  @brief  Permute range into the previous @e dictionary ordering using
+   *          comparison functor.
+   *  @ingroup sorting_algorithms
+   *  @param  __first  Start of range.
+   *  @param  __last   End of range.
+   *  @param  __comp   A comparison functor.
+   *  @return  False if wrapped to last permutation, true otherwise.
+   *
+   *  Treats all permutations of the range [__first,__last) as a set of
+   *  @e dictionary sorted sequences ordered by @p __comp.  Permutes the current
+   *  sequence into the previous one of this set.  Returns true if there are
+   *  more sequences to generate.  If the sequence is the smallest of the set,
+   *  the largest is generated and false returned.
+  */
+  template<typename _BidirectionalIterator, typename _Compare>
+    bool
+    prev_permutation(_BidirectionalIterator __first,
+		     _BidirectionalIterator __last, _Compare __comp)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_BidirectionalIteratorConcept<
+				  _BidirectionalIterator>)
+      __glibcxx_function_requires(_BinaryPredicateConcept<_Compare,
+	    typename iterator_traits<_BidirectionalIterator>::value_type,
+	    typename iterator_traits<_BidirectionalIterator>::value_type>)
+      __glibcxx_requires_valid_range(__first, __last);
+
+      if (__first == __last)
+	return false;
+      _BidirectionalIterator __i = __first;
+      ++__i;
+      if (__i == __last)
+	return false;
+      __i = __last;
+      --__i;
+
+      for(;;)
+	{
+	  _BidirectionalIterator __ii = __i;
+	  --__i;
+	  if (__comp(*__ii, *__i))
+	    {
+	      _BidirectionalIterator __j = __last;
+	      while (!bool(__comp(*--__j, *__i)))
+		{}
+	      std::iter_swap(__i, __j);
+	      std::reverse(__ii, __last);
+	      return true;
+	    }
+	  if (__i == __first)
+	    {
+	      std::reverse(__first, __last);
+	      return false;
+	    }
+	}
+    }
+
+  // replace
+  // replace_if
+
+  /**
+   *  @brief Copy a sequence, replacing each element of one value with another
+   *         value.
+   *  @param  __first      An input iterator.
+   *  @param  __last       An input iterator.
+   *  @param  __result     An output iterator.
+   *  @param  __old_value  The value to be replaced.
+   *  @param  __new_value  The replacement value.
+   *  @return   The end of the output sequence, @p result+(last-first).
+   *
+   *  Copies each element in the input range @p [__first,__last) to the
+   *  output range @p [__result,__result+(__last-__first)) replacing elements
+   *  equal to @p __old_value with @p __new_value.
+  */
+  template<typename _InputIterator, typename _OutputIterator, typename _Tp>
+    _OutputIterator
+    replace_copy(_InputIterator __first, _InputIterator __last,
+		 _OutputIterator __result,
+		 const _Tp& __old_value, const _Tp& __new_value)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)
+      __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,
+	    typename iterator_traits<_InputIterator>::value_type>)
+      __glibcxx_function_requires(_EqualOpConcept<
+	    typename iterator_traits<_InputIterator>::value_type, _Tp>)
+      __glibcxx_requires_valid_range(__first, __last);
+
+      for (; __first != __last; ++__first, ++__result)
+	if (*__first == __old_value)
+	  *__result = __new_value;
+	else
+	  *__result = *__first;
+      return __result;
+    }
+
+  /**
+   *  @brief Copy a sequence, replacing each value for which a predicate
+   *         returns true with another value.
+   *  @ingroup mutating_algorithms
+   *  @param  __first      An input iterator.
+   *  @param  __last       An input iterator.
+   *  @param  __result     An output iterator.
+   *  @param  __pred       A predicate.
+   *  @param  __new_value  The replacement value.
+   *  @return   The end of the output sequence, @p __result+(__last-__first).
+   *
+   *  Copies each element in the range @p [__first,__last) to the range
+   *  @p [__result,__result+(__last-__first)) replacing elements for which
+   *  @p __pred returns true with @p __new_value.
+  */
+  template<typename _InputIterator, typename _OutputIterator,
+	   typename _Predicate, typename _Tp>
+    _OutputIterator
+    replace_copy_if(_InputIterator __first, _InputIterator __last,
+		    _OutputIterator __result,
+		    _Predicate __pred, const _Tp& __new_value)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)
+      __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,
+	    typename iterator_traits<_InputIterator>::value_type>)
+      __glibcxx_function_requires(_UnaryPredicateConcept<_Predicate,
+	    typename iterator_traits<_InputIterator>::value_type>)
+      __glibcxx_requires_valid_range(__first, __last);
+
+      for (; __first != __last; ++__first, ++__result)
+	if (__pred(*__first))
+	  *__result = __new_value;
+	else
+	  *__result = *__first;
+      return __result;
+    }
+
+#if __cplusplus >= 201103L
+  /**
+   *  @brief  Determines whether the elements of a sequence are sorted.
+   *  @ingroup sorting_algorithms
+   *  @param  __first   An iterator.
+   *  @param  __last    Another iterator.
+   *  @return  True if the elements are sorted, false otherwise.
+  */
+  template<typename _ForwardIterator>
+    inline bool
+    is_sorted(_ForwardIterator __first, _ForwardIterator __last)
+    { return std::is_sorted_until(__first, __last) == __last; }
+
+  /**
+   *  @brief  Determines whether the elements of a sequence are sorted
+   *          according to a comparison functor.
+   *  @ingroup sorting_algorithms
+   *  @param  __first   An iterator.
+   *  @param  __last    Another iterator.
+   *  @param  __comp    A comparison functor.
+   *  @return  True if the elements are sorted, false otherwise.
+  */
+  template<typename _ForwardIterator, typename _Compare>
+    inline bool
+    is_sorted(_ForwardIterator __first, _ForwardIterator __last,
+	      _Compare __comp)
+    { return std::is_sorted_until(__first, __last, __comp) == __last; }
+
+  /**
+   *  @brief  Determines the end of a sorted sequence.
+   *  @ingroup sorting_algorithms
+   *  @param  __first   An iterator.
+   *  @param  __last    Another iterator.
+   *  @return  An iterator pointing to the last iterator i in [__first, __last)
+   *           for which the range [__first, i) is sorted.
+  */
+  template<typename _ForwardIterator>
+    _ForwardIterator
+    is_sorted_until(_ForwardIterator __first, _ForwardIterator __last)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)
+      __glibcxx_function_requires(_LessThanComparableConcept<
+	    typename iterator_traits<_ForwardIterator>::value_type>)
+      __glibcxx_requires_valid_range(__first, __last);
+
+      if (__first == __last)
+	return __last;
+
+      _ForwardIterator __next = __first;
+      for (++__next; __next != __last; __first = __next, ++__next)
+	if (*__next < *__first)
+	  return __next;
+      return __next;
+    }
+
+  /**
+   *  @brief  Determines the end of a sorted sequence using comparison functor.
+   *  @ingroup sorting_algorithms
+   *  @param  __first   An iterator.
+   *  @param  __last    Another iterator.
+   *  @param  __comp    A comparison functor.
+   *  @return  An iterator pointing to the last iterator i in [__first, __last)
+   *           for which the range [__first, i) is sorted.
+  */
+  template<typename _ForwardIterator, typename _Compare>
+    _ForwardIterator
+    is_sorted_until(_ForwardIterator __first, _ForwardIterator __last,
+		    _Compare __comp)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)
+      __glibcxx_function_requires(_BinaryPredicateConcept<_Compare,
+	    typename iterator_traits<_ForwardIterator>::value_type,
+	    typename iterator_traits<_ForwardIterator>::value_type>)
+      __glibcxx_requires_valid_range(__first, __last);
+
+      if (__first == __last)
+	return __last;
+
+      _ForwardIterator __next = __first;
+      for (++__next; __next != __last; __first = __next, ++__next)
+	if (__comp(*__next, *__first))
+	  return __next;
+      return __next;
+    }
+
+  /**
+   *  @brief  Determines min and max at once as an ordered pair.
+   *  @ingroup sorting_algorithms
+   *  @param  __a  A thing of arbitrary type.
+   *  @param  __b  Another thing of arbitrary type.
+   *  @return A pair(__b, __a) if __b is smaller than __a, pair(__a,
+   *  __b) otherwise.
+  */
+  template<typename _Tp>
+    inline pair<const _Tp&, const _Tp&>
+    minmax(const _Tp& __a, const _Tp& __b)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_LessThanComparableConcept<_Tp>)
+
+      return __b < __a ? pair<const _Tp&, const _Tp&>(__b, __a)
+	               : pair<const _Tp&, const _Tp&>(__a, __b);
+    }
+
+  /**
+   *  @brief  Determines min and max at once as an ordered pair.
+   *  @ingroup sorting_algorithms
+   *  @param  __a  A thing of arbitrary type.
+   *  @param  __b  Another thing of arbitrary type.
+   *  @param  __comp  A @link comparison_functors comparison functor @endlink.
+   *  @return A pair(__b, __a) if __b is smaller than __a, pair(__a,
+   *  __b) otherwise.
+  */
+  template<typename _Tp, typename _Compare>
+    inline pair<const _Tp&, const _Tp&>
+    minmax(const _Tp& __a, const _Tp& __b, _Compare __comp)
+    {
+      return __comp(__b, __a) ? pair<const _Tp&, const _Tp&>(__b, __a)
+	                      : pair<const _Tp&, const _Tp&>(__a, __b);
+    }
+
+  /**
+   *  @brief  Return a pair of iterators pointing to the minimum and maximum
+   *          elements in a range.
+   *  @ingroup sorting_algorithms
+   *  @param  __first  Start of range.
+   *  @param  __last   End of range.
+   *  @return  make_pair(m, M), where m is the first iterator i in 
+   *           [__first, __last) such that no other element in the range is
+   *           smaller, and where M is the last iterator i in [__first, __last)
+   *           such that no other element in the range is larger.
+  */
+  template<typename _ForwardIterator>
+    pair<_ForwardIterator, _ForwardIterator>
+    minmax_element(_ForwardIterator __first, _ForwardIterator __last)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)
+      __glibcxx_function_requires(_LessThanComparableConcept<
+	    typename iterator_traits<_ForwardIterator>::value_type>)
+      __glibcxx_requires_valid_range(__first, __last);
+
+      _ForwardIterator __next = __first;
+      if (__first == __last
+	  || ++__next == __last)
+	return std::make_pair(__first, __first);
+
+      _ForwardIterator __min, __max;
+      if (*__next < *__first)
+	{
+	  __min = __next;
+	  __max = __first;
+	}
+      else
+	{
+	  __min = __first;
+	  __max = __next;
+	}
+
+      __first = __next;
+      ++__first;
+
+      while (__first != __last)
+	{
+	  __next = __first;
+	  if (++__next == __last)
+	    {
+	      if (*__first < *__min)
+		__min = __first;
+	      else if (!(*__first < *__max))
+		__max = __first;
+	      break;
+	    }
+
+	  if (*__next < *__first)
+	    {
+	      if (*__next < *__min)
+		__min = __next;
+	      if (!(*__first < *__max))
+		__max = __first;
+	    }
+	  else
+	    {
+	      if (*__first < *__min)
+		__min = __first;
+	      if (!(*__next < *__max))
+		__max = __next;
+	    }
+
+	  __first = __next;
+	  ++__first;
+	}
+
+      return std::make_pair(__min, __max);
+    }
+
+  /**
+   *  @brief  Return a pair of iterators pointing to the minimum and maximum
+   *          elements in a range.
+   *  @ingroup sorting_algorithms
+   *  @param  __first  Start of range.
+   *  @param  __last   End of range.
+   *  @param  __comp   Comparison functor.
+   *  @return  make_pair(m, M), where m is the first iterator i in 
+   *           [__first, __last) such that no other element in the range is
+   *           smaller, and where M is the last iterator i in [__first, __last)
+   *           such that no other element in the range is larger.
+  */
+  template<typename _ForwardIterator, typename _Compare>
+    pair<_ForwardIterator, _ForwardIterator>
+    minmax_element(_ForwardIterator __first, _ForwardIterator __last,
+		   _Compare __comp)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)
+      __glibcxx_function_requires(_BinaryPredicateConcept<_Compare,
+	    typename iterator_traits<_ForwardIterator>::value_type,
+	    typename iterator_traits<_ForwardIterator>::value_type>)
+      __glibcxx_requires_valid_range(__first, __last);
+
+      _ForwardIterator __next = __first;
+      if (__first == __last
+	  || ++__next == __last)
+	return std::make_pair(__first, __first);
+
+      _ForwardIterator __min, __max;
+      if (__comp(*__next, *__first))
+	{
+	  __min = __next;
+	  __max = __first;
+	}
+      else
+	{
+	  __min = __first;
+	  __max = __next;
+	}
+
+      __first = __next;
+      ++__first;
+
+      while (__first != __last)
+	{
+	  __next = __first;
+	  if (++__next == __last)
+	    {
+	      if (__comp(*__first, *__min))
+		__min = __first;
+	      else if (!__comp(*__first, *__max))
+		__max = __first;
+	      break;
+	    }
+
+	  if (__comp(*__next, *__first))
+	    {
+	      if (__comp(*__next, *__min))
+		__min = __next;
+	      if (!__comp(*__first, *__max))
+		__max = __first;
+	    }
+	  else
+	    {
+	      if (__comp(*__first, *__min))
+		__min = __first;
+	      if (!__comp(*__next, *__max))
+		__max = __next;
+	    }
+
+	  __first = __next;
+	  ++__first;
+	}
+
+      return std::make_pair(__min, __max);
+    }
+
+  // N2722 + DR 915.
+  template<typename _Tp>
+    inline _Tp
+    min(initializer_list<_Tp> __l)
+    { return *std::min_element(__l.begin(), __l.end()); }
+
+  template<typename _Tp, typename _Compare>
+    inline _Tp
+    min(initializer_list<_Tp> __l, _Compare __comp)
+    { return *std::min_element(__l.begin(), __l.end(), __comp); }
+
+  template<typename _Tp>
+    inline _Tp
+    max(initializer_list<_Tp> __l)
+    { return *std::max_element(__l.begin(), __l.end()); }
+
+  template<typename _Tp, typename _Compare>
+    inline _Tp
+    max(initializer_list<_Tp> __l, _Compare __comp)
+    { return *std::max_element(__l.begin(), __l.end(), __comp); }
+
+  template<typename _Tp>
+    inline pair<_Tp, _Tp>
+    minmax(initializer_list<_Tp> __l)
+    {
+      pair<const _Tp*, const _Tp*> __p =
+	std::minmax_element(__l.begin(), __l.end());
+      return std::make_pair(*__p.first, *__p.second);
+    }
+
+  template<typename _Tp, typename _Compare>
+    inline pair<_Tp, _Tp>
+    minmax(initializer_list<_Tp> __l, _Compare __comp)
+    {
+      pair<const _Tp*, const _Tp*> __p =
+	std::minmax_element(__l.begin(), __l.end(), __comp);
+      return std::make_pair(*__p.first, *__p.second);
+    }
+
+  /**
+   *  @brief  Checks whether a permutaion of the second sequence is equal
+   *          to the first sequence.
+   *  @ingroup non_mutating_algorithms
+   *  @param  __first1  Start of first range.
+   *  @param  __last1   End of first range.
+   *  @param  __first2  Start of second range.
+   *  @return true if there exists a permutation of the elements in the range
+   *          [__first2, __first2 + (__last1 - __first1)), beginning with 
+   *          ForwardIterator2 begin, such that equal(__first1, __last1, begin)
+   *          returns true; otherwise, returns false.
+  */
+  template<typename _ForwardIterator1, typename _ForwardIterator2>
+    bool
+    is_permutation(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
+		   _ForwardIterator2 __first2)
+    {
+      // Efficiently compare identical prefixes:  O(N) if sequences
+      // have the same elements in the same order.
+      for (; __first1 != __last1; ++__first1, ++__first2)
+	if (!(*__first1 == *__first2))
+	  break;
+
+      if (__first1 == __last1)
+	return true;
+
+      // Establish __last2 assuming equal ranges by iterating over the
+      // rest of the list.
+      _ForwardIterator2 __last2 = __first2;
+      std::advance(__last2, std::distance(__first1, __last1));
+      for (_ForwardIterator1 __scan = __first1; __scan != __last1; ++__scan)
+	{
+	  if (__scan != _GLIBCXX_STD_A::find(__first1, __scan, *__scan))
+	    continue; // We've seen this one before.
+
+	  auto __matches = std::count(__first2, __last2, *__scan);
+	  if (0 == __matches
+	      || std::count(__scan, __last1, *__scan) != __matches)
+	    return false;
+	}
+      return true;
+    }
+
+  /**
+   *  @brief  Checks whether a permutation of the second sequence is equal
+   *          to the first sequence.
+   *  @ingroup non_mutating_algorithms
+   *  @param  __first1  Start of first range.
+   *  @param  __last1   End of first range.
+   *  @param  __first2  Start of second range.
+   *  @param  __pred    A binary predicate.
+   *  @return true if there exists a permutation of the elements in
+   *          the range [__first2, __first2 + (__last1 - __first1)),
+   *          beginning with ForwardIterator2 begin, such that
+   *          equal(__first1, __last1, __begin, __pred) returns true;
+   *          otherwise, returns false.
+  */
+  template<typename _ForwardIterator1, typename _ForwardIterator2,
+	   typename _BinaryPredicate>
+    bool
+    is_permutation(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
+		   _ForwardIterator2 __first2, _BinaryPredicate __pred)
+    {
+      // Efficiently compare identical prefixes:  O(N) if sequences
+      // have the same elements in the same order.
+      for (; __first1 != __last1; ++__first1, ++__first2)
+	if (!bool(__pred(*__first1, *__first2)))
+	  break;
+
+      if (__first1 == __last1)
+	return true;
+
+      // Establish __last2 assuming equal ranges by iterating over the
+      // rest of the list.
+      _ForwardIterator2 __last2 = __first2;
+      std::advance(__last2, std::distance(__first1, __last1));
+      for (_ForwardIterator1 __scan = __first1; __scan != __last1; ++__scan)
+	{
+	  using std::placeholders::_1;
+
+	  if (__scan != _GLIBCXX_STD_A::find_if(__first1, __scan,
+						std::bind(__pred, _1, *__scan)))
+	    continue; // We've seen this one before.
+	  
+	  auto __matches = std::count_if(__first2, __last2,
+					 std::bind(__pred, _1, *__scan));
+	  if (0 == __matches
+	      || std::count_if(__scan, __last1,
+			       std::bind(__pred, _1, *__scan)) != __matches)
+	    return false;
+	}
+      return true;
+    }
+
+#ifdef _GLIBCXX_USE_C99_STDINT_TR1
+  /**
+   *  @brief Shuffle the elements of a sequence using a uniform random
+   *         number generator.
+   *  @ingroup mutating_algorithms
+   *  @param  __first   A forward iterator.
+   *  @param  __last    A forward iterator.
+   *  @param  __g       A UniformRandomNumberGenerator (26.5.1.3).
+   *  @return  Nothing.
+   *
+   *  Reorders the elements in the range @p [__first,__last) using @p __g to
+   *  provide random numbers.
+  */
+  template<typename _RandomAccessIterator,
+	   typename _UniformRandomNumberGenerator>
+    void
+    shuffle(_RandomAccessIterator __first, _RandomAccessIterator __last,
+	    _UniformRandomNumberGenerator&& __g)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_Mutable_RandomAccessIteratorConcept<
+	    _RandomAccessIterator>)
+      __glibcxx_requires_valid_range(__first, __last);
+
+      if (__first == __last)
+	return;
+
+      typedef typename iterator_traits<_RandomAccessIterator>::difference_type
+	_DistanceType;
+
+      typedef typename std::make_unsigned<_DistanceType>::type __ud_type;
+      typedef typename std::uniform_int_distribution<__ud_type> __distr_type;
+      typedef typename __distr_type::param_type __p_type;
+      __distr_type __d;
+
+      for (_RandomAccessIterator __i = __first + 1; __i != __last; ++__i)
+	std::iter_swap(__i, __first + __d(__g, __p_type(0, __i - __first)));
+    }
+#endif
+
+#endif // C++11
+
+_GLIBCXX_END_NAMESPACE_VERSION
+
+_GLIBCXX_BEGIN_NAMESPACE_ALGO
+
+  /**
+   *  @brief Apply a function to every element of a sequence.
+   *  @ingroup non_mutating_algorithms
+   *  @param  __first  An input iterator.
+   *  @param  __last   An input iterator.
+   *  @param  __f      A unary function object.
+   *  @return   @p __f (std::move(@p __f) in C++0x).
+   *
+   *  Applies the function object @p __f to each element in the range
+   *  @p [first,last).  @p __f must not modify the order of the sequence.
+   *  If @p __f has a return value it is ignored.
+  */
+  template<typename _InputIterator, typename _Function>
+    _Function
+    for_each(_InputIterator __first, _InputIterator __last, _Function __f)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)
+      __glibcxx_requires_valid_range(__first, __last);
+      for (; __first != __last; ++__first)
+	__f(*__first);
+      return _GLIBCXX_MOVE(__f);
+    }
+
+  /**
+   *  @brief Find the first occurrence of a value in a sequence.
+   *  @ingroup non_mutating_algorithms
+   *  @param  __first  An input iterator.
+   *  @param  __last   An input iterator.
+   *  @param  __val    The value to find.
+   *  @return   The first iterator @c i in the range @p [__first,__last)
+   *  such that @c *i == @p __val, or @p __last if no such iterator exists.
+  */
+  template<typename _InputIterator, typename _Tp>
+    inline _InputIterator
+    find(_InputIterator __first, _InputIterator __last,
+	 const _Tp& __val)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)
+      __glibcxx_function_requires(_EqualOpConcept<
+		typename iterator_traits<_InputIterator>::value_type, _Tp>)
+      __glibcxx_requires_valid_range(__first, __last);
+      return std::__find(__first, __last, __val,
+		         std::__iterator_category(__first));
+    }
+
+  /**
+   *  @brief Find the first element in a sequence for which a
+   *         predicate is true.
+   *  @ingroup non_mutating_algorithms
+   *  @param  __first  An input iterator.
+   *  @param  __last   An input iterator.
+   *  @param  __pred   A predicate.
+   *  @return   The first iterator @c i in the range @p [__first,__last)
+   *  such that @p __pred(*i) is true, or @p __last if no such iterator exists.
+  */
+  template<typename _InputIterator, typename _Predicate>
+    inline _InputIterator
+    find_if(_InputIterator __first, _InputIterator __last,
+	    _Predicate __pred)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)
+      __glibcxx_function_requires(_UnaryPredicateConcept<_Predicate,
+	      typename iterator_traits<_InputIterator>::value_type>)
+      __glibcxx_requires_valid_range(__first, __last);
+      return std::__find_if(__first, __last, __pred,
+			    std::__iterator_category(__first));
+    }
+
+  /**
+   *  @brief  Find element from a set in a sequence.
+   *  @ingroup non_mutating_algorithms
+   *  @param  __first1  Start of range to search.
+   *  @param  __last1   End of range to search.
+   *  @param  __first2  Start of match candidates.
+   *  @param  __last2   End of match candidates.
+   *  @return   The first iterator @c i in the range
+   *  @p [__first1,__last1) such that @c *i == @p *(i2) such that i2 is an
+   *  iterator in [__first2,__last2), or @p __last1 if no such iterator exists.
+   *
+   *  Searches the range @p [__first1,__last1) for an element that is
+   *  equal to some element in the range [__first2,__last2).  If
+   *  found, returns an iterator in the range [__first1,__last1),
+   *  otherwise returns @p __last1.
+  */
+  template<typename _InputIterator, typename _ForwardIterator>
+    _InputIterator
+    find_first_of(_InputIterator __first1, _InputIterator __last1,
+		  _ForwardIterator __first2, _ForwardIterator __last2)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)
+      __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)
+      __glibcxx_function_requires(_EqualOpConcept<
+	    typename iterator_traits<_InputIterator>::value_type,
+	    typename iterator_traits<_ForwardIterator>::value_type>)
+      __glibcxx_requires_valid_range(__first1, __last1);
+      __glibcxx_requires_valid_range(__first2, __last2);
+
+      for (; __first1 != __last1; ++__first1)
+	for (_ForwardIterator __iter = __first2; __iter != __last2; ++__iter)
+	  if (*__first1 == *__iter)
+	    return __first1;
+      return __last1;
+    }
+
+  /**
+   *  @brief  Find element from a set in a sequence using a predicate.
+   *  @ingroup non_mutating_algorithms
+   *  @param  __first1  Start of range to search.
+   *  @param  __last1   End of range to search.
+   *  @param  __first2  Start of match candidates.
+   *  @param  __last2   End of match candidates.
+   *  @param  __comp    Predicate to use.
+   *  @return   The first iterator @c i in the range
+   *  @p [__first1,__last1) such that @c comp(*i, @p *(i2)) is true
+   *  and i2 is an iterator in [__first2,__last2), or @p __last1 if no
+   *  such iterator exists.
+   *
+
+   *  Searches the range @p [__first1,__last1) for an element that is
+   *  equal to some element in the range [__first2,__last2).  If
+   *  found, returns an iterator in the range [__first1,__last1),
+   *  otherwise returns @p __last1.
+  */
+  template<typename _InputIterator, typename _ForwardIterator,
+	   typename _BinaryPredicate>
+    _InputIterator
+    find_first_of(_InputIterator __first1, _InputIterator __last1,
+		  _ForwardIterator __first2, _ForwardIterator __last2,
+		  _BinaryPredicate __comp)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)
+      __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)
+      __glibcxx_function_requires(_BinaryPredicateConcept<_BinaryPredicate,
+	    typename iterator_traits<_InputIterator>::value_type,
+	    typename iterator_traits<_ForwardIterator>::value_type>)
+      __glibcxx_requires_valid_range(__first1, __last1);
+      __glibcxx_requires_valid_range(__first2, __last2);
+
+      for (; __first1 != __last1; ++__first1)
+	for (_ForwardIterator __iter = __first2; __iter != __last2; ++__iter)
+	  if (__comp(*__first1, *__iter))
+	    return __first1;
+      return __last1;
+    }
+
+  /**
+   *  @brief Find two adjacent values in a sequence that are equal.
+   *  @ingroup non_mutating_algorithms
+   *  @param  __first  A forward iterator.
+   *  @param  __last   A forward iterator.
+   *  @return   The first iterator @c i such that @c i and @c i+1 are both
+   *  valid iterators in @p [__first,__last) and such that @c *i == @c *(i+1),
+   *  or @p __last if no such iterator exists.
+  */
+  template<typename _ForwardIterator>
+    _ForwardIterator
+    adjacent_find(_ForwardIterator __first, _ForwardIterator __last)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)
+      __glibcxx_function_requires(_EqualityComparableConcept<
+	    typename iterator_traits<_ForwardIterator>::value_type>)
+      __glibcxx_requires_valid_range(__first, __last);
+      if (__first == __last)
+	return __last;
+      _ForwardIterator __next = __first;
+      while(++__next != __last)
+	{
+	  if (*__first == *__next)
+	    return __first;
+	  __first = __next;
+	}
+      return __last;
+    }
+
+  /**
+   *  @brief Find two adjacent values in a sequence using a predicate.
+   *  @ingroup non_mutating_algorithms
+   *  @param  __first         A forward iterator.
+   *  @param  __last          A forward iterator.
+   *  @param  __binary_pred   A binary predicate.
+   *  @return   The first iterator @c i such that @c i and @c i+1 are both
+   *  valid iterators in @p [__first,__last) and such that
+   *  @p __binary_pred(*i,*(i+1)) is true, or @p __last if no such iterator
+   *  exists.
+  */
+  template<typename _ForwardIterator, typename _BinaryPredicate>
+    _ForwardIterator
+    adjacent_find(_ForwardIterator __first, _ForwardIterator __last,
+		  _BinaryPredicate __binary_pred)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)
+      __glibcxx_function_requires(_BinaryPredicateConcept<_BinaryPredicate,
+	    typename iterator_traits<_ForwardIterator>::value_type,
+	    typename iterator_traits<_ForwardIterator>::value_type>)
+      __glibcxx_requires_valid_range(__first, __last);
+      if (__first == __last)
+	return __last;
+      _ForwardIterator __next = __first;
+      while(++__next != __last)
+	{
+	  if (__binary_pred(*__first, *__next))
+	    return __first;
+	  __first = __next;
+	}
+      return __last;
+    }
+
+  /**
+   *  @brief Count the number of copies of a value in a sequence.
+   *  @ingroup non_mutating_algorithms
+   *  @param  __first  An input iterator.
+   *  @param  __last   An input iterator.
+   *  @param  __value  The value to be counted.
+   *  @return   The number of iterators @c i in the range @p [__first,__last)
+   *  for which @c *i == @p __value
+  */
+  template<typename _InputIterator, typename _Tp>
+    typename iterator_traits<_InputIterator>::difference_type
+    count(_InputIterator __first, _InputIterator __last, const _Tp& __value)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)
+      __glibcxx_function_requires(_EqualOpConcept<
+	typename iterator_traits<_InputIterator>::value_type, _Tp>)
+      __glibcxx_requires_valid_range(__first, __last);
+      typename iterator_traits<_InputIterator>::difference_type __n = 0;
+      for (; __first != __last; ++__first)
+	if (*__first == __value)
+	  ++__n;
+      return __n;
+    }
+
+  /**
+   *  @brief Count the elements of a sequence for which a predicate is true.
+   *  @ingroup non_mutating_algorithms
+   *  @param  __first  An input iterator.
+   *  @param  __last   An input iterator.
+   *  @param  __pred   A predicate.
+   *  @return   The number of iterators @c i in the range @p [__first,__last)
+   *  for which @p __pred(*i) is true.
+  */
+  template<typename _InputIterator, typename _Predicate>
+    typename iterator_traits<_InputIterator>::difference_type
+    count_if(_InputIterator __first, _InputIterator __last, _Predicate __pred)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)
+      __glibcxx_function_requires(_UnaryPredicateConcept<_Predicate,
+	    typename iterator_traits<_InputIterator>::value_type>)
+      __glibcxx_requires_valid_range(__first, __last);
+      typename iterator_traits<_InputIterator>::difference_type __n = 0;
+      for (; __first != __last; ++__first)
+	if (__pred(*__first))
+	  ++__n;
+      return __n;
+    }
+
+  /**
+   *  @brief Search a sequence for a matching sub-sequence.
+   *  @ingroup non_mutating_algorithms
+   *  @param  __first1  A forward iterator.
+   *  @param  __last1   A forward iterator.
+   *  @param  __first2  A forward iterator.
+   *  @param  __last2   A forward iterator.
+   *  @return The first iterator @c i in the range @p
+   *  [__first1,__last1-(__last2-__first2)) such that @c *(i+N) == @p
+   *  *(__first2+N) for each @c N in the range @p
+   *  [0,__last2-__first2), or @p __last1 if no such iterator exists.
+   *
+   *  Searches the range @p [__first1,__last1) for a sub-sequence that
+   *  compares equal value-by-value with the sequence given by @p
+   *  [__first2,__last2) and returns an iterator to the first element
+   *  of the sub-sequence, or @p __last1 if the sub-sequence is not
+   *  found.
+   *
+   *  Because the sub-sequence must lie completely within the range @p
+   *  [__first1,__last1) it must start at a position less than @p
+   *  __last1-(__last2-__first2) where @p __last2-__first2 is the
+   *  length of the sub-sequence.
+   *
+   *  This means that the returned iterator @c i will be in the range
+   *  @p [__first1,__last1-(__last2-__first2))
+  */
+  template<typename _ForwardIterator1, typename _ForwardIterator2>
+    _ForwardIterator1
+    search(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
+	   _ForwardIterator2 __first2, _ForwardIterator2 __last2)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator1>)
+      __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator2>)
+      __glibcxx_function_requires(_EqualOpConcept<
+	    typename iterator_traits<_ForwardIterator1>::value_type,
+	    typename iterator_traits<_ForwardIterator2>::value_type>)
+      __glibcxx_requires_valid_range(__first1, __last1);
+      __glibcxx_requires_valid_range(__first2, __last2);
+
+      // Test for empty ranges
+      if (__first1 == __last1 || __first2 == __last2)
+	return __first1;
+
+      // Test for a pattern of length 1.
+      _ForwardIterator2 __p1(__first2);
+      if (++__p1 == __last2)
+	return _GLIBCXX_STD_A::find(__first1, __last1, *__first2);
+
+      // General case.
+      _ForwardIterator2 __p;
+      _ForwardIterator1 __current = __first1;
+
+      for (;;)
+	{
+	  __first1 = _GLIBCXX_STD_A::find(__first1, __last1, *__first2);
+	  if (__first1 == __last1)
+	    return __last1;
+
+	  __p = __p1;
+	  __current = __first1;
+	  if (++__current == __last1)
+	    return __last1;
+
+	  while (*__current == *__p)
+	    {
+	      if (++__p == __last2)
+		return __first1;
+	      if (++__current == __last1)
+		return __last1;
+	    }
+	  ++__first1;
+	}
+      return __first1;
+    }
+
+  /**
+   *  @brief Search a sequence for a matching sub-sequence using a predicate.
+   *  @ingroup non_mutating_algorithms
+   *  @param  __first1     A forward iterator.
+   *  @param  __last1      A forward iterator.
+   *  @param  __first2     A forward iterator.
+   *  @param  __last2      A forward iterator.
+   *  @param  __predicate  A binary predicate.
+   *  @return   The first iterator @c i in the range
+   *  @p [__first1,__last1-(__last2-__first2)) such that
+   *  @p __predicate(*(i+N),*(__first2+N)) is true for each @c N in the range
+   *  @p [0,__last2-__first2), or @p __last1 if no such iterator exists.
+   *
+   *  Searches the range @p [__first1,__last1) for a sub-sequence that
+   *  compares equal value-by-value with the sequence given by @p
+   *  [__first2,__last2), using @p __predicate to determine equality,
+   *  and returns an iterator to the first element of the
+   *  sub-sequence, or @p __last1 if no such iterator exists.
+   *
+   *  @see search(_ForwardIter1, _ForwardIter1, _ForwardIter2, _ForwardIter2)
+  */
+  template<typename _ForwardIterator1, typename _ForwardIterator2,
+	   typename _BinaryPredicate>
+    _ForwardIterator1
+    search(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
+	   _ForwardIterator2 __first2, _ForwardIterator2 __last2,
+	   _BinaryPredicate  __predicate)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator1>)
+      __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator2>)
+      __glibcxx_function_requires(_BinaryPredicateConcept<_BinaryPredicate,
+	    typename iterator_traits<_ForwardIterator1>::value_type,
+	    typename iterator_traits<_ForwardIterator2>::value_type>)
+      __glibcxx_requires_valid_range(__first1, __last1);
+      __glibcxx_requires_valid_range(__first2, __last2);
+
+      // Test for empty ranges
+      if (__first1 == __last1 || __first2 == __last2)
+	return __first1;
+
+      // Test for a pattern of length 1.
+      _ForwardIterator2 __p1(__first2);
+      if (++__p1 == __last2)
+	{
+	  while (__first1 != __last1
+		 && !bool(__predicate(*__first1, *__first2)))
+	    ++__first1;
+	  return __first1;
+	}
+
+      // General case.
+      _ForwardIterator2 __p;
+      _ForwardIterator1 __current = __first1;
+
+      for (;;)
+	{
+	  while (__first1 != __last1
+		 && !bool(__predicate(*__first1, *__first2)))
+	    ++__first1;
+	  if (__first1 == __last1)
+	    return __last1;
+
+	  __p = __p1;
+	  __current = __first1;
+	  if (++__current == __last1)
+	    return __last1;
+
+	  while (__predicate(*__current, *__p))
+	    {
+	      if (++__p == __last2)
+		return __first1;
+	      if (++__current == __last1)
+		return __last1;
+	    }
+	  ++__first1;
+	}
+      return __first1;
+    }
+
+
+  /**
+   *  @brief Search a sequence for a number of consecutive values.
+   *  @ingroup non_mutating_algorithms
+   *  @param  __first  A forward iterator.
+   *  @param  __last   A forward iterator.
+   *  @param  __count  The number of consecutive values.
+   *  @param  __val    The value to find.
+   *  @return The first iterator @c i in the range @p
+   *  [__first,__last-__count) such that @c *(i+N) == @p __val for
+   *  each @c N in the range @p [0,__count), or @p __last if no such
+   *  iterator exists.
+   *
+   *  Searches the range @p [__first,__last) for @p count consecutive elements
+   *  equal to @p __val.
+  */
+  template<typename _ForwardIterator, typename _Integer, typename _Tp>
+    _ForwardIterator
+    search_n(_ForwardIterator __first, _ForwardIterator __last,
+	     _Integer __count, const _Tp& __val)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)
+      __glibcxx_function_requires(_EqualOpConcept<
+	typename iterator_traits<_ForwardIterator>::value_type, _Tp>)
+      __glibcxx_requires_valid_range(__first, __last);
+
+      if (__count <= 0)
+	return __first;
+      if (__count == 1)
+	return _GLIBCXX_STD_A::find(__first, __last, __val);
+      return std::__search_n(__first, __last, __count, __val,
+			     std::__iterator_category(__first));
+    }
+
+
+  /**
+   *  @brief Search a sequence for a number of consecutive values using a
+   *         predicate.
+   *  @ingroup non_mutating_algorithms
+   *  @param  __first        A forward iterator.
+   *  @param  __last         A forward iterator.
+   *  @param  __count        The number of consecutive values.
+   *  @param  __val          The value to find.
+   *  @param  __binary_pred  A binary predicate.
+   *  @return The first iterator @c i in the range @p
+   *  [__first,__last-__count) such that @p
+   *  __binary_pred(*(i+N),__val) is true for each @c N in the range
+   *  @p [0,__count), or @p __last if no such iterator exists.
+   *
+   *  Searches the range @p [__first,__last) for @p __count
+   *  consecutive elements for which the predicate returns true.
+  */
+  template<typename _ForwardIterator, typename _Integer, typename _Tp,
+           typename _BinaryPredicate>
+    _ForwardIterator
+    search_n(_ForwardIterator __first, _ForwardIterator __last,
+	     _Integer __count, const _Tp& __val,
+	     _BinaryPredicate __binary_pred)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)
+      __glibcxx_function_requires(_BinaryPredicateConcept<_BinaryPredicate,
+	    typename iterator_traits<_ForwardIterator>::value_type, _Tp>)
+      __glibcxx_requires_valid_range(__first, __last);
+
+      if (__count <= 0)
+	return __first;
+      if (__count == 1)
+	{
+	  while (__first != __last && !bool(__binary_pred(*__first, __val)))
+	    ++__first;
+	  return __first;
+	}
+      return std::__search_n(__first, __last, __count, __val, __binary_pred,
+			     std::__iterator_category(__first));
+    }
+
+
+  /**
+   *  @brief Perform an operation on a sequence.
+   *  @ingroup mutating_algorithms
+   *  @param  __first     An input iterator.
+   *  @param  __last      An input iterator.
+   *  @param  __result    An output iterator.
+   *  @param  __unary_op  A unary operator.
+   *  @return   An output iterator equal to @p __result+(__last-__first).
+   *
+   *  Applies the operator to each element in the input range and assigns
+   *  the results to successive elements of the output sequence.
+   *  Evaluates @p *(__result+N)=unary_op(*(__first+N)) for each @c N in the
+   *  range @p [0,__last-__first).
+   *
+   *  @p unary_op must not alter its argument.
+  */
+  template<typename _InputIterator, typename _OutputIterator,
+	   typename _UnaryOperation>
+    _OutputIterator
+    transform(_InputIterator __first, _InputIterator __last,
+	      _OutputIterator __result, _UnaryOperation __unary_op)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)
+      __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,
+            // "the type returned by a _UnaryOperation"
+            __typeof__(__unary_op(*__first))>)
+      __glibcxx_requires_valid_range(__first, __last);
+
+      for (; __first != __last; ++__first, ++__result)
+	*__result = __unary_op(*__first);
+      return __result;
+    }
+
+  /**
+   *  @brief Perform an operation on corresponding elements of two sequences.
+   *  @ingroup mutating_algorithms
+   *  @param  __first1     An input iterator.
+   *  @param  __last1      An input iterator.
+   *  @param  __first2     An input iterator.
+   *  @param  __result     An output iterator.
+   *  @param  __binary_op  A binary operator.
+   *  @return   An output iterator equal to @p result+(last-first).
+   *
+   *  Applies the operator to the corresponding elements in the two
+   *  input ranges and assigns the results to successive elements of the
+   *  output sequence.
+   *  Evaluates @p
+   *  *(__result+N)=__binary_op(*(__first1+N),*(__first2+N)) for each
+   *  @c N in the range @p [0,__last1-__first1).
+   *
+   *  @p binary_op must not alter either of its arguments.
+  */
+  template<typename _InputIterator1, typename _InputIterator2,
+	   typename _OutputIterator, typename _BinaryOperation>
+    _OutputIterator
+    transform(_InputIterator1 __first1, _InputIterator1 __last1,
+	      _InputIterator2 __first2, _OutputIterator __result,
+	      _BinaryOperation __binary_op)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator1>)
+      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator2>)
+      __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,
+            // "the type returned by a _BinaryOperation"
+            __typeof__(__binary_op(*__first1,*__first2))>)
+      __glibcxx_requires_valid_range(__first1, __last1);
+
+      for (; __first1 != __last1; ++__first1, ++__first2, ++__result)
+	*__result = __binary_op(*__first1, *__first2);
+      return __result;
+    }
+
+  /**
+   *  @brief Replace each occurrence of one value in a sequence with another
+   *         value.
+   *  @ingroup mutating_algorithms
+   *  @param  __first      A forward iterator.
+   *  @param  __last       A forward iterator.
+   *  @param  __old_value  The value to be replaced.
+   *  @param  __new_value  The replacement value.
+   *  @return   replace() returns no value.
+   *
+   *  For each iterator @c i in the range @p [__first,__last) if @c *i ==
+   *  @p __old_value then the assignment @c *i = @p __new_value is performed.
+  */
+  template<typename _ForwardIterator, typename _Tp>
+    void
+    replace(_ForwardIterator __first, _ForwardIterator __last,
+	    const _Tp& __old_value, const _Tp& __new_value)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_Mutable_ForwardIteratorConcept<
+				  _ForwardIterator>)
+      __glibcxx_function_requires(_EqualOpConcept<
+	    typename iterator_traits<_ForwardIterator>::value_type, _Tp>)
+      __glibcxx_function_requires(_ConvertibleConcept<_Tp,
+	    typename iterator_traits<_ForwardIterator>::value_type>)
+      __glibcxx_requires_valid_range(__first, __last);
+
+      for (; __first != __last; ++__first)
+	if (*__first == __old_value)
+	  *__first = __new_value;
+    }
+
+  /**
+   *  @brief Replace each value in a sequence for which a predicate returns
+   *         true with another value.
+   *  @ingroup mutating_algorithms
+   *  @param  __first      A forward iterator.
+   *  @param  __last       A forward iterator.
+   *  @param  __pred       A predicate.
+   *  @param  __new_value  The replacement value.
+   *  @return   replace_if() returns no value.
+   *
+   *  For each iterator @c i in the range @p [__first,__last) if @p __pred(*i)
+   *  is true then the assignment @c *i = @p __new_value is performed.
+  */
+  template<typename _ForwardIterator, typename _Predicate, typename _Tp>
+    void
+    replace_if(_ForwardIterator __first, _ForwardIterator __last,
+	       _Predicate __pred, const _Tp& __new_value)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_Mutable_ForwardIteratorConcept<
+				  _ForwardIterator>)
+      __glibcxx_function_requires(_ConvertibleConcept<_Tp,
+	    typename iterator_traits<_ForwardIterator>::value_type>)
+      __glibcxx_function_requires(_UnaryPredicateConcept<_Predicate,
+	    typename iterator_traits<_ForwardIterator>::value_type>)
+      __glibcxx_requires_valid_range(__first, __last);
+
+      for (; __first != __last; ++__first)
+	if (__pred(*__first))
+	  *__first = __new_value;
+    }
+
+  /**
+   *  @brief Assign the result of a function object to each value in a
+   *         sequence.
+   *  @ingroup mutating_algorithms
+   *  @param  __first  A forward iterator.
+   *  @param  __last   A forward iterator.
+   *  @param  __gen    A function object taking no arguments and returning
+   *                 std::iterator_traits<_ForwardIterator>::value_type
+   *  @return   generate() returns no value.
+   *
+   *  Performs the assignment @c *i = @p __gen() for each @c i in the range
+   *  @p [__first,__last).
+  */
+  template<typename _ForwardIterator, typename _Generator>
+    void
+    generate(_ForwardIterator __first, _ForwardIterator __last,
+	     _Generator __gen)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)
+      __glibcxx_function_requires(_GeneratorConcept<_Generator,
+	    typename iterator_traits<_ForwardIterator>::value_type>)
+      __glibcxx_requires_valid_range(__first, __last);
+
+      for (; __first != __last; ++__first)
+	*__first = __gen();
+    }
+
+  /**
+   *  @brief Assign the result of a function object to each value in a
+   *         sequence.
+   *  @ingroup mutating_algorithms
+   *  @param  __first  A forward iterator.
+   *  @param  __n      The length of the sequence.
+   *  @param  __gen    A function object taking no arguments and returning
+   *                 std::iterator_traits<_ForwardIterator>::value_type
+   *  @return   The end of the sequence, @p __first+__n
+   *
+   *  Performs the assignment @c *i = @p __gen() for each @c i in the range
+   *  @p [__first,__first+__n).
+   *
+   *  _GLIBCXX_RESOLVE_LIB_DEFECTS
+   *  DR 865. More algorithms that throw away information
+  */
+  template<typename _OutputIterator, typename _Size, typename _Generator>
+    _OutputIterator
+    generate_n(_OutputIterator __first, _Size __n, _Generator __gen)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,
+            // "the type returned by a _Generator"
+            __typeof__(__gen())>)
+
+      for (__decltype(__n + 0) __niter = __n;
+	   __niter > 0; --__niter, ++__first)
+	*__first = __gen();
+      return __first;
+    }
+
+
+  /**
+   *  @brief Copy a sequence, removing consecutive duplicate values.
+   *  @ingroup mutating_algorithms
+   *  @param  __first   An input iterator.
+   *  @param  __last    An input iterator.
+   *  @param  __result  An output iterator.
+   *  @return   An iterator designating the end of the resulting sequence.
+   *
+   *  Copies each element in the range @p [__first,__last) to the range
+   *  beginning at @p __result, except that only the first element is copied
+   *  from groups of consecutive elements that compare equal.
+   *  unique_copy() is stable, so the relative order of elements that are
+   *  copied is unchanged.
+   *
+   *  _GLIBCXX_RESOLVE_LIB_DEFECTS
+   *  DR 241. Does unique_copy() require CopyConstructible and Assignable?
+   *  
+   *  _GLIBCXX_RESOLVE_LIB_DEFECTS
+   *  DR 538. 241 again: Does unique_copy() require CopyConstructible and 
+   *  Assignable?
+  */
+  template<typename _InputIterator, typename _OutputIterator>
+    inline _OutputIterator
+    unique_copy(_InputIterator __first, _InputIterator __last,
+		_OutputIterator __result)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)
+      __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,
+	    typename iterator_traits<_InputIterator>::value_type>)
+      __glibcxx_function_requires(_EqualityComparableConcept<
+	    typename iterator_traits<_InputIterator>::value_type>)
+      __glibcxx_requires_valid_range(__first, __last);
+
+      if (__first == __last)
+	return __result;
+      return std::__unique_copy(__first, __last, __result,
+				std::__iterator_category(__first),
+				std::__iterator_category(__result));
+    }
+
+  /**
+   *  @brief Copy a sequence, removing consecutive values using a predicate.
+   *  @ingroup mutating_algorithms
+   *  @param  __first        An input iterator.
+   *  @param  __last         An input iterator.
+   *  @param  __result       An output iterator.
+   *  @param  __binary_pred  A binary predicate.
+   *  @return   An iterator designating the end of the resulting sequence.
+   *
+   *  Copies each element in the range @p [__first,__last) to the range
+   *  beginning at @p __result, except that only the first element is copied
+   *  from groups of consecutive elements for which @p __binary_pred returns
+   *  true.
+   *  unique_copy() is stable, so the relative order of elements that are
+   *  copied is unchanged.
+   *
+   *  _GLIBCXX_RESOLVE_LIB_DEFECTS
+   *  DR 241. Does unique_copy() require CopyConstructible and Assignable?
+  */
+  template<typename _InputIterator, typename _OutputIterator,
+	   typename _BinaryPredicate>
+    inline _OutputIterator
+    unique_copy(_InputIterator __first, _InputIterator __last,
+		_OutputIterator __result,
+		_BinaryPredicate __binary_pred)
+    {
+      // concept requirements -- predicates checked later
+      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)
+      __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,
+	    typename iterator_traits<_InputIterator>::value_type>)
+      __glibcxx_requires_valid_range(__first, __last);
+
+      if (__first == __last)
+	return __result;
+      return std::__unique_copy(__first, __last, __result, __binary_pred,
+				std::__iterator_category(__first),
+				std::__iterator_category(__result));
+    }
+
+
+  /**
+   *  @brief Randomly shuffle the elements of a sequence.
+   *  @ingroup mutating_algorithms
+   *  @param  __first   A forward iterator.
+   *  @param  __last    A forward iterator.
+   *  @return  Nothing.
+   *
+   *  Reorder the elements in the range @p [__first,__last) using a random
+   *  distribution, so that every possible ordering of the sequence is
+   *  equally likely.
+  */
+  template<typename _RandomAccessIterator>
+    inline void
+    random_shuffle(_RandomAccessIterator __first, _RandomAccessIterator __last)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_Mutable_RandomAccessIteratorConcept<
+	    _RandomAccessIterator>)
+      __glibcxx_requires_valid_range(__first, __last);
+
+      if (__first != __last)
+	for (_RandomAccessIterator __i = __first + 1; __i != __last; ++__i)
+	  std::iter_swap(__i, __first + (std::rand() % ((__i - __first) + 1)));
+    }
+
+  /**
+   *  @brief Shuffle the elements of a sequence using a random number
+   *         generator.
+   *  @ingroup mutating_algorithms
+   *  @param  __first   A forward iterator.
+   *  @param  __last    A forward iterator.
+   *  @param  __rand    The RNG functor or function.
+   *  @return  Nothing.
+   *
+   *  Reorders the elements in the range @p [__first,__last) using @p __rand to
+   *  provide a random distribution. Calling @p __rand(N) for a positive
+   *  integer @p N should return a randomly chosen integer from the
+   *  range [0,N).
+  */
+  template<typename _RandomAccessIterator, typename _RandomNumberGenerator>
+    void
+    random_shuffle(_RandomAccessIterator __first, _RandomAccessIterator __last,
+#if __cplusplus >= 201103L
+		   _RandomNumberGenerator&& __rand)
+#else
+		   _RandomNumberGenerator& __rand)
+#endif
+    {
+      // concept requirements
+      __glibcxx_function_requires(_Mutable_RandomAccessIteratorConcept<
+	    _RandomAccessIterator>)
+      __glibcxx_requires_valid_range(__first, __last);
+
+      if (__first == __last)
+	return;
+      for (_RandomAccessIterator __i = __first + 1; __i != __last; ++__i)
+	std::iter_swap(__i, __first + __rand((__i - __first) + 1));
+    }
+
+
+  /**
+   *  @brief Move elements for which a predicate is true to the beginning
+   *         of a sequence.
+   *  @ingroup mutating_algorithms
+   *  @param  __first   A forward iterator.
+   *  @param  __last    A forward iterator.
+   *  @param  __pred    A predicate functor.
+   *  @return  An iterator @p middle such that @p __pred(i) is true for each
+   *  iterator @p i in the range @p [__first,middle) and false for each @p i
+   *  in the range @p [middle,__last).
+   *
+   *  @p __pred must not modify its operand. @p partition() does not preserve
+   *  the relative ordering of elements in each group, use
+   *  @p stable_partition() if this is needed.
+  */
+  template<typename _ForwardIterator, typename _Predicate>
+    inline _ForwardIterator
+    partition(_ForwardIterator __first, _ForwardIterator __last,
+	      _Predicate   __pred)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_Mutable_ForwardIteratorConcept<
+				  _ForwardIterator>)
+      __glibcxx_function_requires(_UnaryPredicateConcept<_Predicate,
+	    typename iterator_traits<_ForwardIterator>::value_type>)
+      __glibcxx_requires_valid_range(__first, __last);
+
+      return std::__partition(__first, __last, __pred,
+			      std::__iterator_category(__first));
+    }
+
+
+
+  /**
+   *  @brief Sort the smallest elements of a sequence.
+   *  @ingroup sorting_algorithms
+   *  @param  __first   An iterator.
+   *  @param  __middle  Another iterator.
+   *  @param  __last    Another iterator.
+   *  @return  Nothing.
+   *
+   *  Sorts the smallest @p (__middle-__first) elements in the range
+   *  @p [first,last) and moves them to the range @p [__first,__middle). The
+   *  order of the remaining elements in the range @p [__middle,__last) is
+   *  undefined.
+   *  After the sort if @e i and @e j are iterators in the range
+   *  @p [__first,__middle) such that i precedes j and @e k is an iterator in
+   *  the range @p [__middle,__last) then *j<*i and *k<*i are both false.
+  */
+  template<typename _RandomAccessIterator>
+    inline void
+    partial_sort(_RandomAccessIterator __first,
+		 _RandomAccessIterator __middle,
+		 _RandomAccessIterator __last)
+    {
+      typedef typename iterator_traits<_RandomAccessIterator>::value_type
+	_ValueType;
+
+      // concept requirements
+      __glibcxx_function_requires(_Mutable_RandomAccessIteratorConcept<
+	    _RandomAccessIterator>)
+      __glibcxx_function_requires(_LessThanComparableConcept<_ValueType>)
+      __glibcxx_requires_valid_range(__first, __middle);
+      __glibcxx_requires_valid_range(__middle, __last);
+
+      std::__heap_select(__first, __middle, __last);
+      std::sort_heap(__first, __middle);
+    }
+
+  /**
+   *  @brief Sort the smallest elements of a sequence using a predicate
+   *         for comparison.
+   *  @ingroup sorting_algorithms
+   *  @param  __first   An iterator.
+   *  @param  __middle  Another iterator.
+   *  @param  __last    Another iterator.
+   *  @param  __comp    A comparison functor.
+   *  @return  Nothing.
+   *
+   *  Sorts the smallest @p (__middle-__first) elements in the range
+   *  @p [__first,__last) and moves them to the range @p [__first,__middle). The
+   *  order of the remaining elements in the range @p [__middle,__last) is
+   *  undefined.
+   *  After the sort if @e i and @e j are iterators in the range
+   *  @p [__first,__middle) such that i precedes j and @e k is an iterator in
+   *  the range @p [__middle,__last) then @p *__comp(j,*i) and @p __comp(*k,*i)
+   *  are both false.
+  */
+  template<typename _RandomAccessIterator, typename _Compare>
+    inline void
+    partial_sort(_RandomAccessIterator __first,
+		 _RandomAccessIterator __middle,
+		 _RandomAccessIterator __last,
+		 _Compare __comp)
+    {
+      typedef typename iterator_traits<_RandomAccessIterator>::value_type
+	_ValueType;
+
+      // concept requirements
+      __glibcxx_function_requires(_Mutable_RandomAccessIteratorConcept<
+	    _RandomAccessIterator>)
+      __glibcxx_function_requires(_BinaryPredicateConcept<_Compare,
+				  _ValueType, _ValueType>)
+      __glibcxx_requires_valid_range(__first, __middle);
+      __glibcxx_requires_valid_range(__middle, __last);
+
+      std::__heap_select(__first, __middle, __last, __comp);
+      std::sort_heap(__first, __middle, __comp);
+    }
+
+  /**
+   *  @brief Sort a sequence just enough to find a particular position.
+   *  @ingroup sorting_algorithms
+   *  @param  __first   An iterator.
+   *  @param  __nth     Another iterator.
+   *  @param  __last    Another iterator.
+   *  @return  Nothing.
+   *
+   *  Rearranges the elements in the range @p [__first,__last) so that @p *__nth
+   *  is the same element that would have been in that position had the
+   *  whole sequence been sorted. The elements either side of @p *__nth are
+   *  not completely sorted, but for any iterator @e i in the range
+   *  @p [__first,__nth) and any iterator @e j in the range @p [__nth,__last) it
+   *  holds that *j < *i is false.
+  */
+  template<typename _RandomAccessIterator>
+    inline void
+    nth_element(_RandomAccessIterator __first, _RandomAccessIterator __nth,
+		_RandomAccessIterator __last)
+    {
+      typedef typename iterator_traits<_RandomAccessIterator>::value_type
+	_ValueType;
+
+      // concept requirements
+      __glibcxx_function_requires(_Mutable_RandomAccessIteratorConcept<
+				  _RandomAccessIterator>)
+      __glibcxx_function_requires(_LessThanComparableConcept<_ValueType>)
+      __glibcxx_requires_valid_range(__first, __nth);
+      __glibcxx_requires_valid_range(__nth, __last);
+
+      if (__first == __last || __nth == __last)
+	return;
+
+      std::__introselect(__first, __nth, __last,
+			 std::__lg(__last - __first) * 2);
+    }
+
+  /**
+   *  @brief Sort a sequence just enough to find a particular position
+   *         using a predicate for comparison.
+   *  @ingroup sorting_algorithms
+   *  @param  __first   An iterator.
+   *  @param  __nth     Another iterator.
+   *  @param  __last    Another iterator.
+   *  @param  __comp    A comparison functor.
+   *  @return  Nothing.
+   *
+   *  Rearranges the elements in the range @p [__first,__last) so that @p *__nth
+   *  is the same element that would have been in that position had the
+   *  whole sequence been sorted. The elements either side of @p *__nth are
+   *  not completely sorted, but for any iterator @e i in the range
+   *  @p [__first,__nth) and any iterator @e j in the range @p [__nth,__last) it
+   *  holds that @p __comp(*j,*i) is false.
+  */
+  template<typename _RandomAccessIterator, typename _Compare>
+    inline void
+    nth_element(_RandomAccessIterator __first, _RandomAccessIterator __nth,
+		_RandomAccessIterator __last, _Compare __comp)
+    {
+      typedef typename iterator_traits<_RandomAccessIterator>::value_type
+	_ValueType;
+
+      // concept requirements
+      __glibcxx_function_requires(_Mutable_RandomAccessIteratorConcept<
+				  _RandomAccessIterator>)
+      __glibcxx_function_requires(_BinaryPredicateConcept<_Compare,
+				  _ValueType, _ValueType>)
+      __glibcxx_requires_valid_range(__first, __nth);
+      __glibcxx_requires_valid_range(__nth, __last);
+
+      if (__first == __last || __nth == __last)
+	return;
+
+      std::__introselect(__first, __nth, __last,
+			 std::__lg(__last - __first) * 2, __comp);
+    }
+
+
+  /**
+   *  @brief Sort the elements of a sequence.
+   *  @ingroup sorting_algorithms
+   *  @param  __first   An iterator.
+   *  @param  __last    Another iterator.
+   *  @return  Nothing.
+   *
+   *  Sorts the elements in the range @p [__first,__last) in ascending order,
+   *  such that for each iterator @e i in the range @p [__first,__last-1),  
+   *  *(i+1)<*i is false.
+   *
+   *  The relative ordering of equivalent elements is not preserved, use
+   *  @p stable_sort() if this is needed.
+  */
+  template<typename _RandomAccessIterator>
+    inline void
+    sort(_RandomAccessIterator __first, _RandomAccessIterator __last)
+    {
+      typedef typename iterator_traits<_RandomAccessIterator>::value_type
+	_ValueType;
+
+      // concept requirements
+      __glibcxx_function_requires(_Mutable_RandomAccessIteratorConcept<
+	    _RandomAccessIterator>)
+      __glibcxx_function_requires(_LessThanComparableConcept<_ValueType>)
+      __glibcxx_requires_valid_range(__first, __last);
+
+      if (__first != __last)
+	{
+	  std::__introsort_loop(__first, __last,
+				std::__lg(__last - __first) * 2);
+	  std::__final_insertion_sort(__first, __last);
+	}
+    }
+
+  /**
+   *  @brief Sort the elements of a sequence using a predicate for comparison.
+   *  @ingroup sorting_algorithms
+   *  @param  __first   An iterator.
+   *  @param  __last    Another iterator.
+   *  @param  __comp    A comparison functor.
+   *  @return  Nothing.
+   *
+   *  Sorts the elements in the range @p [__first,__last) in ascending order,
+   *  such that @p __comp(*(i+1),*i) is false for every iterator @e i in the
+   *  range @p [__first,__last-1).
+   *
+   *  The relative ordering of equivalent elements is not preserved, use
+   *  @p stable_sort() if this is needed.
+  */
+  template<typename _RandomAccessIterator, typename _Compare>
+    inline void
+    sort(_RandomAccessIterator __first, _RandomAccessIterator __last,
+	 _Compare __comp)
+    {
+      typedef typename iterator_traits<_RandomAccessIterator>::value_type
+	_ValueType;
+
+      // concept requirements
+      __glibcxx_function_requires(_Mutable_RandomAccessIteratorConcept<
+	    _RandomAccessIterator>)
+      __glibcxx_function_requires(_BinaryPredicateConcept<_Compare, _ValueType,
+				  _ValueType>)
+      __glibcxx_requires_valid_range(__first, __last);
+
+      if (__first != __last)
+	{
+	  std::__introsort_loop(__first, __last,
+				std::__lg(__last - __first) * 2, __comp);
+	  std::__final_insertion_sort(__first, __last, __comp);
+	}
+    }
+
+  /**
+   *  @brief Merges two sorted ranges.
+   *  @ingroup sorting_algorithms
+   *  @param  __first1  An iterator.
+   *  @param  __first2  Another iterator.
+   *  @param  __last1   Another iterator.
+   *  @param  __last2   Another iterator.
+   *  @param  __result  An iterator pointing to the end of the merged range.
+   *  @return         An iterator pointing to the first element <em>not less
+   *                  than</em> @e val.
+   *
+   *  Merges the ranges @p [__first1,__last1) and @p [__first2,__last2) into
+   *  the sorted range @p [__result, __result + (__last1-__first1) +
+   *  (__last2-__first2)).  Both input ranges must be sorted, and the
+   *  output range must not overlap with either of the input ranges.
+   *  The sort is @e stable, that is, for equivalent elements in the
+   *  two ranges, elements from the first range will always come
+   *  before elements from the second.
+  */
+  template<typename _InputIterator1, typename _InputIterator2,
+	   typename _OutputIterator>
+    _OutputIterator
+    merge(_InputIterator1 __first1, _InputIterator1 __last1,
+	  _InputIterator2 __first2, _InputIterator2 __last2,
+	  _OutputIterator __result)
+    {
+      typedef typename iterator_traits<_InputIterator1>::value_type
+	_ValueType1;
+      typedef typename iterator_traits<_InputIterator2>::value_type
+	_ValueType2;
+
+      // concept requirements
+      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator1>)
+      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator2>)
+      __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,
+				  _ValueType1>)
+      __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,
+				  _ValueType2>)
+      __glibcxx_function_requires(_LessThanOpConcept<_ValueType2, _ValueType1>)	
+      __glibcxx_requires_sorted_set(__first1, __last1, __first2);
+      __glibcxx_requires_sorted_set(__first2, __last2, __first1);
+
+      while (__first1 != __last1 && __first2 != __last2)
+	{
+	  if (*__first2 < *__first1)
+	    {
+	      *__result = *__first2;
+	      ++__first2;
+	    }
+	  else
+	    {
+	      *__result = *__first1;
+	      ++__first1;
+	    }
+	  ++__result;
+	}
+      return std::copy(__first2, __last2, std::copy(__first1, __last1,
+						    __result));
+    }
+
+  /**
+   *  @brief Merges two sorted ranges.
+   *  @ingroup sorting_algorithms
+   *  @param  __first1  An iterator.
+   *  @param  __first2  Another iterator.
+   *  @param  __last1   Another iterator.
+   *  @param  __last2   Another iterator.
+   *  @param  __result  An iterator pointing to the end of the merged range.
+   *  @param  __comp    A functor to use for comparisons.
+   *  @return         An iterator pointing to the first element "not less
+   *                  than" @e val.
+   *
+   *  Merges the ranges @p [__first1,__last1) and @p [__first2,__last2) into
+   *  the sorted range @p [__result, __result + (__last1-__first1) +
+   *  (__last2-__first2)).  Both input ranges must be sorted, and the
+   *  output range must not overlap with either of the input ranges.
+   *  The sort is @e stable, that is, for equivalent elements in the
+   *  two ranges, elements from the first range will always come
+   *  before elements from the second.
+   *
+   *  The comparison function should have the same effects on ordering as
+   *  the function used for the initial sort.
+  */
+  template<typename _InputIterator1, typename _InputIterator2,
+	   typename _OutputIterator, typename _Compare>
+    _OutputIterator
+    merge(_InputIterator1 __first1, _InputIterator1 __last1,
+	  _InputIterator2 __first2, _InputIterator2 __last2,
+	  _OutputIterator __result, _Compare __comp)
+    {
+      typedef typename iterator_traits<_InputIterator1>::value_type
+	_ValueType1;
+      typedef typename iterator_traits<_InputIterator2>::value_type
+	_ValueType2;
+
+      // concept requirements
+      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator1>)
+      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator2>)
+      __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,
+				  _ValueType1>)
+      __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,
+				  _ValueType2>)
+      __glibcxx_function_requires(_BinaryPredicateConcept<_Compare,
+				  _ValueType2, _ValueType1>)
+      __glibcxx_requires_sorted_set_pred(__first1, __last1, __first2, __comp);
+      __glibcxx_requires_sorted_set_pred(__first2, __last2, __first1, __comp);
+
+      while (__first1 != __last1 && __first2 != __last2)
+	{
+	  if (__comp(*__first2, *__first1))
+	    {
+	      *__result = *__first2;
+	      ++__first2;
+	    }
+	  else
+	    {
+	      *__result = *__first1;
+	      ++__first1;
+	    }
+	  ++__result;
+	}
+      return std::copy(__first2, __last2, std::copy(__first1, __last1,
+						    __result));
+    }
+
+
+  /**
+   *  @brief Sort the elements of a sequence, preserving the relative order
+   *         of equivalent elements.
+   *  @ingroup sorting_algorithms
+   *  @param  __first   An iterator.
+   *  @param  __last    Another iterator.
+   *  @return  Nothing.
+   *
+   *  Sorts the elements in the range @p [__first,__last) in ascending order,
+   *  such that for each iterator @p i in the range @p [__first,__last-1),
+   *  @p *(i+1)<*i is false.
+   *
+   *  The relative ordering of equivalent elements is preserved, so any two
+   *  elements @p x and @p y in the range @p [__first,__last) such that
+   *  @p x<y is false and @p y<x is false will have the same relative
+   *  ordering after calling @p stable_sort().
+  */
+  template<typename _RandomAccessIterator>
+    inline void
+    stable_sort(_RandomAccessIterator __first, _RandomAccessIterator __last)
+    {
+      typedef typename iterator_traits<_RandomAccessIterator>::value_type
+	_ValueType;
+      typedef typename iterator_traits<_RandomAccessIterator>::difference_type
+	_DistanceType;
+
+      // concept requirements
+      __glibcxx_function_requires(_Mutable_RandomAccessIteratorConcept<
+	    _RandomAccessIterator>)
+      __glibcxx_function_requires(_LessThanComparableConcept<_ValueType>)
+      __glibcxx_requires_valid_range(__first, __last);
+
+      _Temporary_buffer<_RandomAccessIterator, _ValueType> __buf(__first,
+								 __last);
+      if (__buf.begin() == 0)
+	std::__inplace_stable_sort(__first, __last);
+      else
+	std::__stable_sort_adaptive(__first, __last, __buf.begin(),
+				    _DistanceType(__buf.size()));
+    }
+
+  /**
+   *  @brief Sort the elements of a sequence using a predicate for comparison,
+   *         preserving the relative order of equivalent elements.
+   *  @ingroup sorting_algorithms
+   *  @param  __first   An iterator.
+   *  @param  __last    Another iterator.
+   *  @param  __comp    A comparison functor.
+   *  @return  Nothing.
+   *
+   *  Sorts the elements in the range @p [__first,__last) in ascending order,
+   *  such that for each iterator @p i in the range @p [__first,__last-1),
+   *  @p __comp(*(i+1),*i) is false.
+   *
+   *  The relative ordering of equivalent elements is preserved, so any two
+   *  elements @p x and @p y in the range @p [__first,__last) such that
+   *  @p __comp(x,y) is false and @p __comp(y,x) is false will have the same
+   *  relative ordering after calling @p stable_sort().
+  */
+  template<typename _RandomAccessIterator, typename _Compare>
+    inline void
+    stable_sort(_RandomAccessIterator __first, _RandomAccessIterator __last,
+		_Compare __comp)
+    {
+      typedef typename iterator_traits<_RandomAccessIterator>::value_type
+	_ValueType;
+      typedef typename iterator_traits<_RandomAccessIterator>::difference_type
+	_DistanceType;
+
+      // concept requirements
+      __glibcxx_function_requires(_Mutable_RandomAccessIteratorConcept<
+	    _RandomAccessIterator>)
+      __glibcxx_function_requires(_BinaryPredicateConcept<_Compare,
+				  _ValueType,
+				  _ValueType>)
+      __glibcxx_requires_valid_range(__first, __last);
+
+      _Temporary_buffer<_RandomAccessIterator, _ValueType> __buf(__first,
+								 __last);
+      if (__buf.begin() == 0)
+	std::__inplace_stable_sort(__first, __last, __comp);
+      else
+	std::__stable_sort_adaptive(__first, __last, __buf.begin(),
+				    _DistanceType(__buf.size()), __comp);
+    }
+
+
+  /**
+   *  @brief Return the union of two sorted ranges.
+   *  @ingroup set_algorithms
+   *  @param  __first1  Start of first range.
+   *  @param  __last1   End of first range.
+   *  @param  __first2  Start of second range.
+   *  @param  __last2   End of second range.
+   *  @return  End of the output range.
+   *  @ingroup set_algorithms
+   *
+   *  This operation iterates over both ranges, copying elements present in
+   *  each range in order to the output range.  Iterators increment for each
+   *  range.  When the current element of one range is less than the other,
+   *  that element is copied and the iterator advanced.  If an element is
+   *  contained in both ranges, the element from the first range is copied and
+   *  both ranges advance.  The output range may not overlap either input
+   *  range.
+  */
+  template<typename _InputIterator1, typename _InputIterator2,
+	   typename _OutputIterator>
+    _OutputIterator
+    set_union(_InputIterator1 __first1, _InputIterator1 __last1,
+	      _InputIterator2 __first2, _InputIterator2 __last2,
+	      _OutputIterator __result)
+    {
+      typedef typename iterator_traits<_InputIterator1>::value_type
+	_ValueType1;
+      typedef typename iterator_traits<_InputIterator2>::value_type
+	_ValueType2;
+
+      // concept requirements
+      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator1>)
+      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator2>)
+      __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,
+				  _ValueType1>)
+      __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,
+				  _ValueType2>)
+      __glibcxx_function_requires(_LessThanOpConcept<_ValueType1, _ValueType2>)
+      __glibcxx_function_requires(_LessThanOpConcept<_ValueType2, _ValueType1>)
+      __glibcxx_requires_sorted_set(__first1, __last1, __first2);
+      __glibcxx_requires_sorted_set(__first2, __last2, __first1);
+
+      while (__first1 != __last1 && __first2 != __last2)
+	{
+	  if (*__first1 < *__first2)
+	    {
+	      *__result = *__first1;
+	      ++__first1;
+	    }
+	  else if (*__first2 < *__first1)
+	    {
+	      *__result = *__first2;
+	      ++__first2;
+	    }
+	  else
+	    {
+	      *__result = *__first1;
+	      ++__first1;
+	      ++__first2;
+	    }
+	  ++__result;
+	}
+      return std::copy(__first2, __last2, std::copy(__first1, __last1,
+						    __result));
+    }
+
+  /**
+   *  @brief Return the union of two sorted ranges using a comparison functor.
+   *  @ingroup set_algorithms
+   *  @param  __first1  Start of first range.
+   *  @param  __last1   End of first range.
+   *  @param  __first2  Start of second range.
+   *  @param  __last2   End of second range.
+   *  @param  __comp    The comparison functor.
+   *  @return  End of the output range.
+   *  @ingroup set_algorithms
+   *
+   *  This operation iterates over both ranges, copying elements present in
+   *  each range in order to the output range.  Iterators increment for each
+   *  range.  When the current element of one range is less than the other
+   *  according to @p __comp, that element is copied and the iterator advanced.
+   *  If an equivalent element according to @p __comp is contained in both
+   *  ranges, the element from the first range is copied and both ranges
+   *  advance.  The output range may not overlap either input range.
+  */
+  template<typename _InputIterator1, typename _InputIterator2,
+	   typename _OutputIterator, typename _Compare>
+    _OutputIterator
+    set_union(_InputIterator1 __first1, _InputIterator1 __last1,
+	      _InputIterator2 __first2, _InputIterator2 __last2,
+	      _OutputIterator __result, _Compare __comp)
+    {
+      typedef typename iterator_traits<_InputIterator1>::value_type
+	_ValueType1;
+      typedef typename iterator_traits<_InputIterator2>::value_type
+	_ValueType2;
+
+      // concept requirements
+      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator1>)
+      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator2>)
+      __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,
+				  _ValueType1>)
+      __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,
+				  _ValueType2>)
+      __glibcxx_function_requires(_BinaryPredicateConcept<_Compare,
+				  _ValueType1, _ValueType2>)
+      __glibcxx_function_requires(_BinaryPredicateConcept<_Compare,
+				  _ValueType2, _ValueType1>)
+      __glibcxx_requires_sorted_set_pred(__first1, __last1, __first2, __comp);
+      __glibcxx_requires_sorted_set_pred(__first2, __last2, __first1, __comp);
+
+      while (__first1 != __last1 && __first2 != __last2)
+	{
+	  if (__comp(*__first1, *__first2))
+	    {
+	      *__result = *__first1;
+	      ++__first1;
+	    }
+	  else if (__comp(*__first2, *__first1))
+	    {
+	      *__result = *__first2;
+	      ++__first2;
+	    }
+	  else
+	    {
+	      *__result = *__first1;
+	      ++__first1;
+	      ++__first2;
+	    }
+	  ++__result;
+	}
+      return std::copy(__first2, __last2, std::copy(__first1, __last1,
+						    __result));
+    }
+
+  /**
+   *  @brief Return the intersection of two sorted ranges.
+   *  @ingroup set_algorithms
+   *  @param  __first1  Start of first range.
+   *  @param  __last1   End of first range.
+   *  @param  __first2  Start of second range.
+   *  @param  __last2   End of second range.
+   *  @return  End of the output range.
+   *  @ingroup set_algorithms
+   *
+   *  This operation iterates over both ranges, copying elements present in
+   *  both ranges in order to the output range.  Iterators increment for each
+   *  range.  When the current element of one range is less than the other,
+   *  that iterator advances.  If an element is contained in both ranges, the
+   *  element from the first range is copied and both ranges advance.  The
+   *  output range may not overlap either input range.
+  */
+  template<typename _InputIterator1, typename _InputIterator2,
+	   typename _OutputIterator>
+    _OutputIterator
+    set_intersection(_InputIterator1 __first1, _InputIterator1 __last1,
+		     _InputIterator2 __first2, _InputIterator2 __last2,
+		     _OutputIterator __result)
+    {
+      typedef typename iterator_traits<_InputIterator1>::value_type
+	_ValueType1;
+      typedef typename iterator_traits<_InputIterator2>::value_type
+	_ValueType2;
+
+      // concept requirements
+      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator1>)
+      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator2>)
+      __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,
+				  _ValueType1>)
+      __glibcxx_function_requires(_LessThanOpConcept<_ValueType1, _ValueType2>)
+      __glibcxx_function_requires(_LessThanOpConcept<_ValueType2, _ValueType1>)
+      __glibcxx_requires_sorted_set(__first1, __last1, __first2);
+      __glibcxx_requires_sorted_set(__first2, __last2, __first1);
+
+      while (__first1 != __last1 && __first2 != __last2)
+	if (*__first1 < *__first2)
+	  ++__first1;
+	else if (*__first2 < *__first1)
+	  ++__first2;
+	else
+	  {
+	    *__result = *__first1;
+	    ++__first1;
+	    ++__first2;
+	    ++__result;
+	  }
+      return __result;
+    }
+
+  /**
+   *  @brief Return the intersection of two sorted ranges using comparison
+   *  functor.
+   *  @ingroup set_algorithms
+   *  @param  __first1  Start of first range.
+   *  @param  __last1   End of first range.
+   *  @param  __first2  Start of second range.
+   *  @param  __last2   End of second range.
+   *  @param  __comp    The comparison functor.
+   *  @return  End of the output range.
+   *  @ingroup set_algorithms
+   *
+   *  This operation iterates over both ranges, copying elements present in
+   *  both ranges in order to the output range.  Iterators increment for each
+   *  range.  When the current element of one range is less than the other
+   *  according to @p __comp, that iterator advances.  If an element is
+   *  contained in both ranges according to @p __comp, the element from the
+   *  first range is copied and both ranges advance.  The output range may not
+   *  overlap either input range.
+  */
+  template<typename _InputIterator1, typename _InputIterator2,
+	   typename _OutputIterator, typename _Compare>
+    _OutputIterator
+    set_intersection(_InputIterator1 __first1, _InputIterator1 __last1,
+		     _InputIterator2 __first2, _InputIterator2 __last2,
+		     _OutputIterator __result, _Compare __comp)
+    {
+      typedef typename iterator_traits<_InputIterator1>::value_type
+	_ValueType1;
+      typedef typename iterator_traits<_InputIterator2>::value_type
+	_ValueType2;
+
+      // concept requirements
+      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator1>)
+      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator2>)
+      __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,
+				  _ValueType1>)
+      __glibcxx_function_requires(_BinaryPredicateConcept<_Compare,
+				  _ValueType1, _ValueType2>)
+      __glibcxx_function_requires(_BinaryPredicateConcept<_Compare,
+				  _ValueType2, _ValueType1>)
+      __glibcxx_requires_sorted_set_pred(__first1, __last1, __first2, __comp);
+      __glibcxx_requires_sorted_set_pred(__first2, __last2, __first1, __comp);
+
+      while (__first1 != __last1 && __first2 != __last2)
+	if (__comp(*__first1, *__first2))
+	  ++__first1;
+	else if (__comp(*__first2, *__first1))
+	  ++__first2;
+	else
+	  {
+	    *__result = *__first1;
+	    ++__first1;
+	    ++__first2;
+	    ++__result;
+	  }
+      return __result;
+    }
+
+  /**
+   *  @brief Return the difference of two sorted ranges.
+   *  @ingroup set_algorithms
+   *  @param  __first1  Start of first range.
+   *  @param  __last1   End of first range.
+   *  @param  __first2  Start of second range.
+   *  @param  __last2   End of second range.
+   *  @return  End of the output range.
+   *  @ingroup set_algorithms
+   *
+   *  This operation iterates over both ranges, copying elements present in
+   *  the first range but not the second in order to the output range.
+   *  Iterators increment for each range.  When the current element of the
+   *  first range is less than the second, that element is copied and the
+   *  iterator advances.  If the current element of the second range is less,
+   *  the iterator advances, but no element is copied.  If an element is
+   *  contained in both ranges, no elements are copied and both ranges
+   *  advance.  The output range may not overlap either input range.
+  */
+  template<typename _InputIterator1, typename _InputIterator2,
+	   typename _OutputIterator>
+    _OutputIterator
+    set_difference(_InputIterator1 __first1, _InputIterator1 __last1,
+		   _InputIterator2 __first2, _InputIterator2 __last2,
+		   _OutputIterator __result)
+    {
+      typedef typename iterator_traits<_InputIterator1>::value_type
+	_ValueType1;
+      typedef typename iterator_traits<_InputIterator2>::value_type
+	_ValueType2;
+
+      // concept requirements
+      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator1>)
+      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator2>)
+      __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,
+				  _ValueType1>)
+      __glibcxx_function_requires(_LessThanOpConcept<_ValueType1, _ValueType2>)
+      __glibcxx_function_requires(_LessThanOpConcept<_ValueType2, _ValueType1>)	
+      __glibcxx_requires_sorted_set(__first1, __last1, __first2);
+      __glibcxx_requires_sorted_set(__first2, __last2, __first1);
+
+      while (__first1 != __last1 && __first2 != __last2)
+	if (*__first1 < *__first2)
+	  {
+	    *__result = *__first1;
+	    ++__first1;
+	    ++__result;
+	  }
+	else if (*__first2 < *__first1)
+	  ++__first2;
+	else
+	  {
+	    ++__first1;
+	    ++__first2;
+	  }
+      return std::copy(__first1, __last1, __result);
+    }
+
+  /**
+   *  @brief  Return the difference of two sorted ranges using comparison
+   *  functor.
+   *  @ingroup set_algorithms
+   *  @param  __first1  Start of first range.
+   *  @param  __last1   End of first range.
+   *  @param  __first2  Start of second range.
+   *  @param  __last2   End of second range.
+   *  @param  __comp    The comparison functor.
+   *  @return  End of the output range.
+   *  @ingroup set_algorithms
+   *
+   *  This operation iterates over both ranges, copying elements present in
+   *  the first range but not the second in order to the output range.
+   *  Iterators increment for each range.  When the current element of the
+   *  first range is less than the second according to @p __comp, that element
+   *  is copied and the iterator advances.  If the current element of the
+   *  second range is less, no element is copied and the iterator advances.
+   *  If an element is contained in both ranges according to @p __comp, no
+   *  elements are copied and both ranges advance.  The output range may not
+   *  overlap either input range.
+  */
+  template<typename _InputIterator1, typename _InputIterator2,
+	   typename _OutputIterator, typename _Compare>
+    _OutputIterator
+    set_difference(_InputIterator1 __first1, _InputIterator1 __last1,
+		   _InputIterator2 __first2, _InputIterator2 __last2,
+		   _OutputIterator __result, _Compare __comp)
+    {
+      typedef typename iterator_traits<_InputIterator1>::value_type
+	_ValueType1;
+      typedef typename iterator_traits<_InputIterator2>::value_type
+	_ValueType2;
+
+      // concept requirements
+      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator1>)
+      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator2>)
+      __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,
+				  _ValueType1>)
+      __glibcxx_function_requires(_BinaryPredicateConcept<_Compare,
+				  _ValueType1, _ValueType2>)
+      __glibcxx_function_requires(_BinaryPredicateConcept<_Compare,
+				  _ValueType2, _ValueType1>)
+      __glibcxx_requires_sorted_set_pred(__first1, __last1, __first2, __comp);
+      __glibcxx_requires_sorted_set_pred(__first2, __last2, __first1, __comp);
+
+      while (__first1 != __last1 && __first2 != __last2)
+	if (__comp(*__first1, *__first2))
+	  {
+	    *__result = *__first1;
+	    ++__first1;
+	    ++__result;
+	  }
+	else if (__comp(*__first2, *__first1))
+	  ++__first2;
+	else
+	  {
+	    ++__first1;
+	    ++__first2;
+	  }
+      return std::copy(__first1, __last1, __result);
+    }
+
+  /**
+   *  @brief  Return the symmetric difference of two sorted ranges.
+   *  @ingroup set_algorithms
+   *  @param  __first1  Start of first range.
+   *  @param  __last1   End of first range.
+   *  @param  __first2  Start of second range.
+   *  @param  __last2   End of second range.
+   *  @return  End of the output range.
+   *  @ingroup set_algorithms
+   *
+   *  This operation iterates over both ranges, copying elements present in
+   *  one range but not the other in order to the output range.  Iterators
+   *  increment for each range.  When the current element of one range is less
+   *  than the other, that element is copied and the iterator advances.  If an
+   *  element is contained in both ranges, no elements are copied and both
+   *  ranges advance.  The output range may not overlap either input range.
+  */
+  template<typename _InputIterator1, typename _InputIterator2,
+	   typename _OutputIterator>
+    _OutputIterator
+    set_symmetric_difference(_InputIterator1 __first1, _InputIterator1 __last1,
+			     _InputIterator2 __first2, _InputIterator2 __last2,
+			     _OutputIterator __result)
+    {
+      typedef typename iterator_traits<_InputIterator1>::value_type
+	_ValueType1;
+      typedef typename iterator_traits<_InputIterator2>::value_type
+	_ValueType2;
+
+      // concept requirements
+      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator1>)
+      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator2>)
+      __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,
+				  _ValueType1>)
+      __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,
+				  _ValueType2>)
+      __glibcxx_function_requires(_LessThanOpConcept<_ValueType1, _ValueType2>)
+      __glibcxx_function_requires(_LessThanOpConcept<_ValueType2, _ValueType1>)	
+      __glibcxx_requires_sorted_set(__first1, __last1, __first2);
+      __glibcxx_requires_sorted_set(__first2, __last2, __first1);
+
+      while (__first1 != __last1 && __first2 != __last2)
+	if (*__first1 < *__first2)
+	  {
+	    *__result = *__first1;
+	    ++__first1;
+	    ++__result;
+	  }
+	else if (*__first2 < *__first1)
+	  {
+	    *__result = *__first2;
+	    ++__first2;
+	    ++__result;
+	  }
+	else
+	  {
+	    ++__first1;
+	    ++__first2;
+	  }
+      return std::copy(__first2, __last2, std::copy(__first1,
+						    __last1, __result));
+    }
+
+  /**
+   *  @brief  Return the symmetric difference of two sorted ranges using
+   *  comparison functor.
+   *  @ingroup set_algorithms
+   *  @param  __first1  Start of first range.
+   *  @param  __last1   End of first range.
+   *  @param  __first2  Start of second range.
+   *  @param  __last2   End of second range.
+   *  @param  __comp    The comparison functor.
+   *  @return  End of the output range.
+   *  @ingroup set_algorithms
+   *
+   *  This operation iterates over both ranges, copying elements present in
+   *  one range but not the other in order to the output range.  Iterators
+   *  increment for each range.  When the current element of one range is less
+   *  than the other according to @p comp, that element is copied and the
+   *  iterator advances.  If an element is contained in both ranges according
+   *  to @p __comp, no elements are copied and both ranges advance.  The output
+   *  range may not overlap either input range.
+  */
+  template<typename _InputIterator1, typename _InputIterator2,
+	   typename _OutputIterator, typename _Compare>
+    _OutputIterator
+    set_symmetric_difference(_InputIterator1 __first1, _InputIterator1 __last1,
+			     _InputIterator2 __first2, _InputIterator2 __last2,
+			     _OutputIterator __result,
+			     _Compare __comp)
+    {
+      typedef typename iterator_traits<_InputIterator1>::value_type
+	_ValueType1;
+      typedef typename iterator_traits<_InputIterator2>::value_type
+	_ValueType2;
+
+      // concept requirements
+      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator1>)
+      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator2>)
+      __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,
+				  _ValueType1>)
+      __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,
+				  _ValueType2>)
+      __glibcxx_function_requires(_BinaryPredicateConcept<_Compare,
+				  _ValueType1, _ValueType2>)
+      __glibcxx_function_requires(_BinaryPredicateConcept<_Compare,
+				  _ValueType2, _ValueType1>)
+      __glibcxx_requires_sorted_set_pred(__first1, __last1, __first2, __comp);
+      __glibcxx_requires_sorted_set_pred(__first2, __last2, __first1, __comp);
+
+      while (__first1 != __last1 && __first2 != __last2)
+	if (__comp(*__first1, *__first2))
+	  {
+	    *__result = *__first1;
+	    ++__first1;
+	    ++__result;
+	  }
+	else if (__comp(*__first2, *__first1))
+	  {
+	    *__result = *__first2;
+	    ++__first2;
+	    ++__result;
+	  }
+	else
+	  {
+	    ++__first1;
+	    ++__first2;
+	  }
+      return std::copy(__first2, __last2, 
+		       std::copy(__first1, __last1, __result));
+    }
+
+
+  /**
+   *  @brief  Return the minimum element in a range.
+   *  @ingroup sorting_algorithms
+   *  @param  __first  Start of range.
+   *  @param  __last   End of range.
+   *  @return  Iterator referencing the first instance of the smallest value.
+  */
+  template<typename _ForwardIterator>
+    _ForwardIterator
+    min_element(_ForwardIterator __first, _ForwardIterator __last)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)
+      __glibcxx_function_requires(_LessThanComparableConcept<
+	    typename iterator_traits<_ForwardIterator>::value_type>)
+      __glibcxx_requires_valid_range(__first, __last);
+
+      if (__first == __last)
+	return __first;
+      _ForwardIterator __result = __first;
+      while (++__first != __last)
+	if (*__first < *__result)
+	  __result = __first;
+      return __result;
+    }
+
+  /**
+   *  @brief  Return the minimum element in a range using comparison functor.
+   *  @ingroup sorting_algorithms
+   *  @param  __first  Start of range.
+   *  @param  __last   End of range.
+   *  @param  __comp   Comparison functor.
+   *  @return  Iterator referencing the first instance of the smallest value
+   *  according to __comp.
+  */
+  template<typename _ForwardIterator, typename _Compare>
+    _ForwardIterator
+    min_element(_ForwardIterator __first, _ForwardIterator __last,
+		_Compare __comp)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)
+      __glibcxx_function_requires(_BinaryPredicateConcept<_Compare,
+	    typename iterator_traits<_ForwardIterator>::value_type,
+	    typename iterator_traits<_ForwardIterator>::value_type>)
+      __glibcxx_requires_valid_range(__first, __last);
+
+      if (__first == __last)
+	return __first;
+      _ForwardIterator __result = __first;
+      while (++__first != __last)
+	if (__comp(*__first, *__result))
+	  __result = __first;
+      return __result;
+    }
+
+  /**
+   *  @brief  Return the maximum element in a range.
+   *  @ingroup sorting_algorithms
+   *  @param  __first  Start of range.
+   *  @param  __last   End of range.
+   *  @return  Iterator referencing the first instance of the largest value.
+  */
+  template<typename _ForwardIterator>
+    _ForwardIterator
+    max_element(_ForwardIterator __first, _ForwardIterator __last)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)
+      __glibcxx_function_requires(_LessThanComparableConcept<
+	    typename iterator_traits<_ForwardIterator>::value_type>)
+      __glibcxx_requires_valid_range(__first, __last);
+
+      if (__first == __last)
+	return __first;
+      _ForwardIterator __result = __first;
+      while (++__first != __last)
+	if (*__result < *__first)
+	  __result = __first;
+      return __result;
+    }
+
+  /**
+   *  @brief  Return the maximum element in a range using comparison functor.
+   *  @ingroup sorting_algorithms
+   *  @param  __first  Start of range.
+   *  @param  __last   End of range.
+   *  @param  __comp   Comparison functor.
+   *  @return  Iterator referencing the first instance of the largest value
+   *  according to __comp.
+  */
+  template<typename _ForwardIterator, typename _Compare>
+    _ForwardIterator
+    max_element(_ForwardIterator __first, _ForwardIterator __last,
+		_Compare __comp)
+    {
+      // concept requirements
+      __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)
+      __glibcxx_function_requires(_BinaryPredicateConcept<_Compare,
+	    typename iterator_traits<_ForwardIterator>::value_type,
+	    typename iterator_traits<_ForwardIterator>::value_type>)
+      __glibcxx_requires_valid_range(__first, __last);
+
+      if (__first == __last) return __first;
+      _ForwardIterator __result = __first;
+      while (++__first != __last)
+	if (__comp(*__result, *__first))
+	  __result = __first;
+      return __result;
+    }
+
+_GLIBCXX_END_NAMESPACE_ALGO
+} // namespace std
+
+#endif /* _STL_ALGO_H */
diff -r 540d1c122b08 -r 0d660785098e configure.ac
--- a/configure.ac	Thu Nov 07 12:37:13 2013 -0500
+++ b/configure.ac	Thu Nov 07 14:03:58 2013 -0500
@@ -342,6 +342,7 @@
 
 GCC_VERSION=
 if test "$GCC" = yes; then
+  AC_MSG_CHECKING([C compiler version number])
   gcc_version=`$CC -v 2>&1 | $GREP "^.*gcc version" | \
     $SED -e 's/^.*g.. version *//' -e 's/cygnus-//' -e 's/egcs-//' -e 's/ .*//'`
 
@@ -350,6 +351,7 @@
      OCTAVE_CONFIGURE_WARNING([warn_gcc_version])])
 
   GCC_VERSION=$gcc_version
+  AC_MSG_RESULT([$GCC_VERSION])
 fi
 AC_SUBST(GCC_VERSION)
 
@@ -362,7 +364,8 @@
 
 GXX_VERSION=
 if test "$GXX" = yes; then
-  gxx_version=`$CXX -v 2>&1 | $GREP "^.*g++ version" | \
+  AC_MSG_CHECKING([C++ compiler version number])
+  gxx_version=`$CXX -v 2>&1 | $GREP "^.*g.. version" | \
     $SED -e 's/^.*g.. version *//' -e 's/cygnus-//' -e 's/egcs-//' -e 's/ .*//'`
 
   AX_COMPARE_VERSION([$gxx_version], [lt], [3],
@@ -370,9 +373,14 @@
      OCTAVE_CONFIGURE_WARNING([warn_gxx_version])])
 
   GXX_VERSION=$gxx_version
+  AC_MSG_RESULT([$GXX_VERSION])
 fi
 AC_SUBST(GXX_VERSION)
 
+OCTAVE_CHECK_BROKEN_STL_ALGO_H
+AM_CONDITIONAL([AMCOND_HAVE_BROKEN_STL_ALGO_H],
+  [test $octave_cv_broken_stl_algo_h = yes])
+
 ### Determine the compiler flag necessary to create dependencies
 
 ## Assume GCC.
diff -r 540d1c122b08 -r 0d660785098e m4/acinclude.m4
--- a/m4/acinclude.m4	Thu Nov 07 12:37:13 2013 -0500
+++ b/m4/acinclude.m4	Thu Nov 07 14:03:58 2013 -0500
@@ -2057,6 +2057,85 @@
   fi
 ])
 
+AC_DEFUN([OCTAVE_CHECK_BROKEN_STL_ALGO_H], [
+  AC_CACHE_CHECK([whether stl_algo.h is broken],
+    [octave_cv_broken_stl_algo_h],
+    [AC_LANG_PUSH(C++)
+    AC_RUN_IFELSE([AC_LANG_PROGRAM([[
+// Based on code from a GCC test program.
+
+// Copyright (C) 2013 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library. This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License along
+// with this library; see the file COPYING3. If not see
+// <http://www.gnu.org/licenses/>.
+
+// 25.3.2 [lib.alg.nth.element]
+
+// { dg-options "-std=gnu++11" }
+
+#include <algorithm>
+#include <vector>
+      ]], [[
+std::vector<int> v (7);
+
+v[0] = 207089;
+v[1] = 202585;
+v[2] = 180067;
+v[3] = 157549;
+v[4] = 211592;
+v[5] = 216096;
+v[6] = 207089;
+
+std::nth_element (v.begin (), v.begin () + 3, v.end ());
+
+return v[3] == 207089 ? 0 : 1;
+    ]])],
+    octave_cv_broken_stl_algo_h=no,
+    octave_cv_broken_stl_algo_h=yes,
+    [case "$GXX_VERSION" in
+       *4.8.2*)
+         octave_cv_broken_stl_algo_h=yes,
+       ;;
+     esac
+    ])
+    AC_LANG_POP(C++)
+  ])
+  if test "$GXX" = yes; then
+    if test $octave_cv_broken_stl_algo_h = yes; then
+      case "$GXX_VERSION" in
+        4.8.2)
+        ;;
+        *)
+          warn_stl_algo_h="UNEXPECTED: found stl_algo.h broken in $GXX_VERSION"
+          OCTAVE_CONFIGURE_WARNING([warn_stl_algo_h])
+        ;;
+      esac
+    else
+      case "$GXX_VERSION" in
+        4.8.2)
+          warn_stl_algo_h="UNEXPECTED: found stl_algo.h working in g++ $GXX_VERSION -- has it been patched on your system?"
+          OCTAVE_CONFIGURE_WARNING([warn_stl_algo_h])
+        ;;
+      esac
+    fi
+  else
+    warn_stl_algo_h="UNEXPECTED: nth_element test failed (expected only for g++ 4.8.2)"
+    OCTAVE_CONFIGURE_WARNING([warn_stl_algo_h])
+  fi
+])
+
 dnl         End of macros written by Octave developers
 dnl ------------------------------------------------------------
 dnl