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@lo8pi59d
此快照首次捕获于
2023/10/27 22:26
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今天我编译自己码的程序后直接跳到了这串程序并给我报错,请问这是什么东西,为什么编译的时候会给我弹到这来报错? 使用软件:Dev-c++。
CPP
// Algorithm implementation -*- C++ -*-

// Copyright (C) 2001-2014 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
#include <bits/predefined_ops.h>

#if __cplusplus >= 201103L
#include <random>     // for std::uniform_int_distribution
#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 under __comp to *__result
  template<typename _Iterator, typename _Compare>
    void
    __move_median_to_first(_Iterator __result,_Iterator __a, _Iterator __b,
			   _Iterator __c, _Compare __comp)
    {
      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);
    }

  /// This is an overload used by find algos 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 && !__pred(__first))
	++__first;
      return __first;
    }

  /// This is an overload used by find algos 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;
	}
    }

  template<typename _Iterator, typename _Predicate>
    inline _Iterator
    __find_if(_Iterator __first, _Iterator __last, _Predicate __pred)
    {
      return __find_if(__first, __last, __pred,
		       std::__iterator_category(__first));
    }

  /// 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(__first, __last,
			    __gnu_cxx::__ops::__negate(__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 (!__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

  template<typename _ForwardIterator1, typename _ForwardIterator2,
	   typename _BinaryPredicate>
    _ForwardIterator1
    __search(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
	     _ForwardIterator2 __first2, _ForwardIterator2 __last2,
	     _BinaryPredicate  __predicate)
    {
      // 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 std::__find_if(__first1, __last1,
		__gnu_cxx::__ops::__iter_comp_iter(__predicate, __first2));

      // General case.
      _ForwardIterator2 __p;
      _ForwardIterator1 __current = __first1;

      for (;;)
	{
	  __first1 =
	    std::__find_if(__first1, __last1,
		__gnu_cxx::__ops::__iter_comp_iter(__predicate, __first2));

	  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;
    }

  // search_n

  /**
   *  This is an helper function for search_n overloaded for forward iterators.
  */
  template<typename _ForwardIterator, typename _Integer,
	   typename _UnaryPredicate>
    _ForwardIterator
    __search_n_aux(_ForwardIterator __first, _ForwardIterator __last,
		   _Integer __count, _UnaryPredicate __unary_pred,
		   std::forward_iterator_tag)
    {
      __first = std::__find_if(__first, __last, __unary_pred);
      while (__first != __last)
	{
	  typename iterator_traits<_ForwardIterator>::difference_type
	    __n = __count;
	  _ForwardIterator __i = __first;
	  ++__i;
	  while (__i != __last && __n != 1 && __unary_pred(__i))
	    {
	      ++__i;
	      --__n;
	    }
	  if (__n == 1)
	    return __first;
	  if (__i == __last)
	    return __last;
	  __first = std::__find_if(++__i, __last, __unary_pred);
	}
      return __last;
    }

  /**
   *  This is an helper function for search_n overloaded for random access
   *  iterators.
  */
  template<typename _RandomAccessIter, typename _Integer,
	   typename _UnaryPredicate>
    _RandomAccessIter
    __search_n_aux(_RandomAccessIter __first, _RandomAccessIter __last,
		   _Integer __count, _UnaryPredicate __unary_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 (__unary_pred(--__backTrack))
	    {
	      if (--__remainder == 0)
	        return (__first - __count); // Success
	    }
	  __remainder = __count + 1 - (__first - __backTrack);
	}
      return __last; // Failure
    }

  template<typename _ForwardIterator, typename _Integer,
           typename _UnaryPredicate>
    _ForwardIterator
    __search_n(_ForwardIterator __first, _ForwardIterator __last,
	       _Integer __count,
	       _UnaryPredicate __unary_pred)
    {
      if (__count <= 0)
	return __first;

      if (__count == 1)
	return std::__find_if(__first, __last, __unary_pred);

      return std::__search_n_aux(__first, __last, __count, __unary_pred,
				 std::__iterator_category(__first));
    }

  // find_end for forward iterators.
  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;

      _ForwardIterator1 __result = __last1;
      while (1)
	{
	  _ForwardIterator1 __new_result
	    = std::__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,
	   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 [__first1,__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),
			     __gnu_cxx::__ops::__iter_equal_to_iter());
    }

  /**
   *  @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),
			     __gnu_cxx::__ops::__iter_comp_iter(__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,
				__gnu_cxx::__ops::__pred_iter(__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

  template<typename _InputIterator, typename _OutputIterator,
	   typename _Predicate>
    _OutputIterator
    __remove_copy_if(_InputIterator __first, _InputIterator __last,
		     _OutputIterator __result, _Predicate __pred)
    {
      for (; __first != __last; ++__first)
	if (!__pred(__first))
	  {
	    *__result = *__first;
	    ++__result;
	  }
      return __result;
    }

  /**
   *  @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>
    inline _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);

      return std::__remove_copy_if(__first, __last, __result,
	__gnu_cxx::__ops::__iter_equals_val(__value));
    }

  /**
   *  @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>
    inline _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);

      return std::__remove_copy_if(__first, __last, __result,
				   __gnu_cxx::__ops::__pred_iter(__pred));
    }

#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

  template<typename _ForwardIterator, typename _Predicate>
    _ForwardIterator
    __remove_if(_ForwardIterator __first, _ForwardIterator __last,
		_Predicate __pred)
    {
      __first = std::__find_if(__first, __last, __pred);
      if (__first == __last)
        return __first;
      _ForwardIterator __result = __first;
      ++__first;
      for (; __first != __last; ++__first)
        if (!__pred(__first))
          {
            *__result = _GLIBCXX_MOVE(*__first);
            ++__result;
          }
      return __result;
    }

  /**
   *  @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>
    inline _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);

      return std::__remove_if(__first, __last,
		__gnu_cxx::__ops::__iter_equals_val(__value));
    }

  /**
   *  @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>
    inline _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);

      return std::__remove_if(__first, __last,
			      __gnu_cxx::__ops::__pred_iter(__pred));
    }

  template<typename _ForwardIterator, typename _BinaryPredicate>
    _ForwardIterator
    __adjacent_find(_ForwardIterator __first, _ForwardIterator __last,
		    _BinaryPredicate __binary_pred)
    {
      if (__first == __last)
	return __last;
      _ForwardIterator __next = __first;
      while (++__next != __last)
	{
	  if (__binary_pred(__first, __next))
	    return __first;
	  __first = __next;
	}
      return __last;
    }

  template<typename _ForwardIterator, typename _BinaryPredicate>
    _ForwardIterator
    __unique(_ForwardIterator __first, _ForwardIterator __last,
	     _BinaryPredicate __binary_pred)
    {
      // Skip the beginning, if already unique.
      __first = std::__adjacent_find(__first, __last, __binary_pred);
      if (__first == __last)
	return __last;

      // Do the real copy work.
      _ForwardIterator __dest = __first;
      ++__first;
      while (++__first != __last)
	if (!__binary_pred(__dest, __first))
	  *++__dest = _GLIBCXX_MOVE(*__first);
      return ++__dest;
    }

  /**
   *  @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>
    inline _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);

      return std::__unique(__first, __last,
			   __gnu_cxx::__ops::__iter_equal_to_iter());
    }

  /**
   *  @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>
    inline _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);

      return std::__unique(__first, __last,
			   __gnu_cxx::__ops::__iter_comp_iter(__binary_pred));
    }

  /**
   *  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 (!__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;
      __decltype(__gnu_cxx::__ops::__iter_comp_val(__binary_pred))
	__rebound_pred
	= __gnu_cxx::__ops::__iter_comp_val(__binary_pred);
      *__result = __value;
      while (++__first != __last)
	if (!__rebound_pred(__first, __value))
	  {
	    __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 (!__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);

      std::__rotate(__first, __middle, __last,
		    std::__iterator_category(__first));
    }

  /**
   *  @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>
    inline _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;
	}
    }

  template<typename _ForwardIterator, typename _Predicate>
    _ForwardIterator
    __stable_partition(_ForwardIterator __first, _ForwardIterator __last,
		       _Predicate __pred)
    {
      __first = std::__find_if_not(__first, __last, __pred);

      if (__first == __last)
	return __first;

      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()));
    }

  /**
   *  @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>
    inline _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);

      return std::__stable_partition(__first, __last,
				     __gnu_cxx::__ops::__pred_iter(__pred));
    }

  /// 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

  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 iterator_traits<_RandomAccessIterator> _RItTraits;
      typedef typename _RItTraits::difference_type _DistanceType;

      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;
    }

  /**
   *  @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>
    inline _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);

      return std::__partial_sort_copy(__first, __last,
				      __result_first, __result_last,
				      __gnu_cxx::__ops::__iter_less_iter());
    }

  /**
   *  @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>
    inline _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);

      return std::__partial_sort_copy(__first, __last,
				      __result_first, __result_last,
				__gnu_cxx::__ops::__iter_comp_iter(__comp));
    }

  /// 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, 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,
				__gnu_cxx::__ops::__val_comp_iter(__comp));
	}
    }

  /// 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)
    {
      for (_RandomAccessIterator __i = __first; __i != __last; ++__i)
	std::__unguarded_linear_insert(__i,
				__gnu_cxx::__ops::__val_comp_iter(__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, 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 _Compare>
    _RandomAccessIterator
    __unguarded_partition(_RandomAccessIterator __first,
			  _RandomAccessIterator __last,
			  _RandomAccessIterator __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, typename _Compare>
    inline _RandomAccessIterator
    __unguarded_partition_pivot(_RandomAccessIterator __first,
				_RandomAccessIterator __last, _Compare __comp)
    {
      _RandomAccessIterator __mid 

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