algorithm.h

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/******************************************************************************
The MIT License(MIT)
 
Embedded Template Library.
https://github.com/ETLCPP/etl
https://www.etlcpp.com
 
Documentation: https://www.etlcpp.com/algorithm.html
 
Copyright(c) 2014 John Wellbelove
 
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files(the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and / or sell
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The above copyright notice and this permission notice shall be included in all
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IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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******************************************************************************/
 
#ifndef ETL_ALGORITHM_INCLUDED
#define ETL_ALGORITHM_INCLUDED

 
#include "platform.h"
#include "type_traits.h"
#include "iterator.h"
#include "functional.h"
#include "utility.h"
#include "largest.h"
#include "gcd.h"
#include "error_handler.h"
#include "exception.h"
 
#include <stdint.h>
#include <string.h>
 
#include "private/minmax_push.h"
 
#if ETL_USING_STL
  #include <algorithm>
  #include <utility>
  #include <iterator>
  #include <functional>
  #include <numeric>
#endif
 
namespace etl
{
  // Declare prototypes of the ETL's sort functions
  template <typename TIterator>
#if ETL_USING_STD_NAMESPACE
  ETL_CONSTEXPR20 
#else
  ETL_CONSTEXPR14
#endif
  void shell_sort(TIterator first, TIterator last);
 
  template <typename TIterator, typename TCompare>
#if ETL_USING_STD_NAMESPACE
  ETL_CONSTEXPR20
#else
  ETL_CONSTEXPR14
#endif
  void shell_sort(TIterator first, TIterator last, TCompare compare);
 
  template <typename TIterator>
  ETL_CONSTEXPR14 void insertion_sort(TIterator first, TIterator last);
 
  template <typename TIterator, typename TCompare>
  ETL_CONSTEXPR14 void insertion_sort(TIterator first, TIterator last, TCompare compare);
 
  class algorithm_exception : public etl::exception
  {
  public:
 
    algorithm_exception(string_type reason_, string_type file_name_, numeric_type line_number_)
      : exception(reason_, file_name_, line_number_)
    {
    }
  };
 
  class algorithm_error : public algorithm_exception
  {
  public:
 
    algorithm_error(string_type file_name_, numeric_type line_number_)
      : algorithm_exception(ETL_ERROR_TEXT("algorithm:error", ETL_ALGORITHM_FILE_ID"A"), file_name_, line_number_)
    {
    }
  };
 
}
 
//*****************************************************************************
// Algorithms defined by the ETL
//*****************************************************************************
namespace etl
{
  namespace private_algorithm
  {
    template <bool use_swap>
    struct swap_impl;
 
    // Generic swap
    template <>
    struct swap_impl<false>
    {
      template <typename TIterator1, typename TIterator2>
      static void do_swap(TIterator1 a, TIterator2 b)
      {
        typename etl::iterator_traits<TIterator1>::value_type tmp = *a;
        *a = *b;
        *b = tmp;
      }
    };
 
    // Specialised swap
    template <>
    struct swap_impl<true>
    {
      template <typename TIterator1, typename TIterator2>
      static void do_swap(TIterator1 a, TIterator2 b)
      {
        using ETL_OR_STD::swap; // Allow ADL
        swap(*a, *b);
      }
    };
  }
 
  //***************************************************************************
  // iter_swap
  //***************************************************************************
  template <typename TIterator1, typename TIterator2>
#if ETL_USING_STD_NAMESPACE
  ETL_CONSTEXPR20
#else
  ETL_CONSTEXPR14
#endif
  void iter_swap(TIterator1 a, TIterator2 b)
  {
    typedef etl::iterator_traits<TIterator1> traits1;
    typedef etl::iterator_traits<TIterator2> traits2;
 
    typedef typename traits1::value_type v1;
    typedef typename traits2::value_type v2;
 
    typedef typename traits1::reference r1;
    typedef typename traits2::reference r2;
 
    const bool use_swap = etl::is_same<v1, v2>::value  &&
                          etl::is_reference<r1>::value &&
                          etl::is_reference<r2>::value;
 
    private_algorithm::swap_impl<use_swap>::do_swap(a, b);
  }
 
  //***************************************************************************
  // swap_ranges
  //***************************************************************************
  template <typename TIterator1, typename TIterator2>
#if ETL_USING_STD_NAMESPACE
  ETL_CONSTEXPR20
#else
  ETL_CONSTEXPR14
#endif
  TIterator2 swap_ranges(TIterator1 first1,
                         TIterator1 last1,
                         TIterator2 first2)
  {
    while (first1 != last1)
    {
      iter_swap(first1, first2);
      ++first1;
      ++first2;
    }
 
    return first2;
  }
 
  //***************************************************************************
  // generate
  template <typename TIterator, typename TFunction>
  ETL_CONSTEXPR14
  void generate(TIterator db, TIterator de, TFunction funct)
  {
    while (db != de)
    {
      *db++ = funct();
    }
  }
 
  //***************************************************************************
  // copy
#if ETL_USING_STL && ETL_USING_CPP20 
  // Use the STL constexpr implementation.
  template <typename TIterator1, typename TIterator2>
  constexpr TIterator2 copy(TIterator1 sb, TIterator1 se, TIterator2 db)
  {
    return std::copy(sb, se, db);
  }
#else
  // Non-pointer or not trivially copyable or not using builtin memcpy.
  template <typename TIterator1, typename TIterator2>
  ETL_CONSTEXPR14 TIterator2 copy(TIterator1 sb, TIterator1 se, TIterator2 db)
  {
    while (sb != se)
    {
      *db = *sb;
      ++db;
      ++sb;
    }
 
    return db;
  }
#endif
 
  //***************************************************************************
  // reverse_copy
#if ETL_USING_STL && ETL_USING_CPP20
  template <typename TIterator1, typename TIterator2>
  constexpr TIterator2 reverse_copy(TIterator1 sb, TIterator1 se, TIterator2 db)
  {
    return std::reverse_copy(sb, se, db);
  }
#else
  template <typename TIterator1, typename TIterator2>
  ETL_CONSTEXPR14
  TIterator2 reverse_copy(TIterator1 sb, TIterator1 se, TIterator2 db)
  {
    while (sb != se)
    {
      *db = *--se;
      ++db;
    }
 
    return db;
  }
#endif
 
  //***************************************************************************
  // copy_n
#if ETL_USING_STL && ETL_USING_CPP20
  // Use the STL implementation
  template <typename TIterator1, typename TSize, typename TIterator2>
  constexpr TIterator2 copy_n(TIterator1 sb, TSize count, TIterator2 db)
  {
    return std::copy_n(sb, count, db);
  }
#else
  // Non-pointer or not trivially copyable or not using builtin memcpy.
  template <typename TIterator1, typename TSize, typename TIterator2>
  ETL_CONSTEXPR14 TIterator2 copy_n(TIterator1 sb, TSize count, TIterator2 db)
  {
    while (count != 0)
    {
      *db = *sb;
      ++db;
      ++sb;
      --count;
    }
 
    return db;
  }
#endif
 
  //***************************************************************************
  // copy_backward
#if ETL_USING_STL && ETL_USING_CPP20
  template <typename TIterator1, typename TIterator2>
  constexpr TIterator2 copy_backward(TIterator1 sb, TIterator1 se, TIterator2 de)
  {
    return std::copy_backward(sb, se, de);
  }
#else
  template <typename TIterator1, typename TIterator2>
  ETL_CONSTEXPR14 TIterator2 copy_backward(TIterator1 sb, TIterator1 se, TIterator2 de)
  {
    while (se != sb)
    {
      *(--de) = *(--se);
    }
 
    return de;
  }
#endif
 
  //***************************************************************************
  // move
#if ETL_USING_STL && ETL_USING_CPP20
  template <typename TIterator1, typename TIterator2>
  constexpr TIterator2 move(TIterator1 sb, TIterator1 se, TIterator2 db)
  {
    return std::move(sb, se, db);
  }
#elif ETL_USING_CPP11
  // For C++11
  template <typename TIterator1, typename TIterator2>
  ETL_CONSTEXPR14 TIterator2 move(TIterator1 sb, TIterator1 se, TIterator2 db)
  {
    while (sb != se)
    {
      *db = etl::move(*sb);
      ++db;
      ++sb;
    }
 
    return db;
  }
#else
  // For C++03
  template <typename TIterator1, typename TIterator2>
  ETL_CONSTEXPR14 TIterator2 move(TIterator1 sb, TIterator1 se, TIterator2 db)
  {
    return copy(sb, se, db);
  }
#endif
 
  //***************************************************************************
  // move_backward
#if ETL_USING_STL && ETL_USING_CPP20
  template <typename TIterator1, typename TIterator2>
  ETL_CONSTEXPR20 TIterator2 move_backward(TIterator1 sb, TIterator1 se, TIterator2 de)
  {
    return std::move_backward(sb, se, de);
  }
#elif ETL_USING_CPP11
  // For C++11
  template <typename TIterator1, typename TIterator2>
  ETL_CONSTEXPR14 TIterator2 move_backward(TIterator1 sb, TIterator1 se, TIterator2 de)
  {
    while (sb != se)
    {
      *(--de) = etl::move(*(--se));
    }
 
    return de;
  }
#else
  // For C++03
  template <typename TIterator1, typename TIterator2>
  ETL_CONSTEXPR14 TIterator2 move_backward(TIterator1 sb, TIterator1 se, TIterator2 de)
  {
    return etl::copy_backward(sb, se, de);
  }
#endif
 
  //***************************************************************************
  // reverse
  //***************************************************************************
  // Pointers
  template <typename TIterator>
  ETL_CONSTEXPR14
  typename etl::enable_if<etl::is_pointer<TIterator>::value, void>::type
    reverse(TIterator b, TIterator e)
  {
    if (b != e)
    {
      while (b < --e)
      {
        etl::iter_swap(b, e);
        ++b;
      }
    }
  }
 
  // Non-pointers
  template <typename TIterator>
  ETL_CONSTEXPR14
  typename etl::enable_if<!etl::is_pointer<TIterator>::value, void>::type
    reverse(TIterator b, TIterator e)
  {
    while ((b != e) && (b != --e))
    {
      etl::iter_swap(b++, e);
    }
  }
 
  //***************************************************************************
  // lower_bound
  //***************************************************************************
  template<typename TIterator, typename TValue, typename TCompare>
  ETL_NODISCARD
  ETL_CONSTEXPR14
  TIterator lower_bound(TIterator first, TIterator last, const TValue& value, TCompare compare)
  {
    typedef typename etl::iterator_traits<TIterator>::difference_type difference_t;
 
    difference_t count = etl::distance(first, last);
 
    while (count > 0)
    {
      TIterator    itr = first;
      difference_t step = count / 2;
 
      etl::advance(itr, step);
 
      if (compare(*itr, value))
      {
        first = ++itr;
        count -= step + 1;
      }
      else
      {
        count = step;
      }
    }
 
    return first;
  }
 
  template<typename TIterator, typename TValue>
  ETL_NODISCARD
  ETL_CONSTEXPR14
  TIterator lower_bound(TIterator first, TIterator last, const TValue& value)
  {
    typedef etl::less<typename etl::iterator_traits<TIterator>::value_type> compare;
 
    return etl::lower_bound(first, last, value, compare());
  }
 
  //***************************************************************************
  // upper_bound
  //***************************************************************************
  template<typename TIterator, typename TValue, typename TCompare>
  ETL_NODISCARD
  ETL_CONSTEXPR14
  TIterator upper_bound(TIterator first, TIterator last, const TValue& value, TCompare compare)
  {
    typedef typename etl::iterator_traits<TIterator>::difference_type difference_t;
 
    difference_t count = etl::distance(first, last);
 
    while (count > 0)
    {
      TIterator    itr = first;
      difference_t step = count / 2;
 
      etl::advance(itr, step);
 
      if (!compare(value, *itr))
      {
        first = ++itr;
        count -= step + 1;
      }
      else
      {
        count = step;
      }
    }
 
    return first;
  }
 
  template<typename TIterator, typename TValue>
  ETL_NODISCARD
  ETL_CONSTEXPR14
  TIterator upper_bound(TIterator first, TIterator last, const TValue& value)
  {
    typedef etl::less<typename etl::iterator_traits<TIterator>::value_type> compare;
 
    return etl::upper_bound(first, last, value, compare());
  }
 
  //***************************************************************************
  // equal_range
  //***************************************************************************
  template<typename TIterator, typename TValue, typename TCompare>
  ETL_NODISCARD
  ETL_CONSTEXPR14
  ETL_OR_STD::pair<TIterator, TIterator> equal_range(TIterator first, TIterator last, const TValue& value, TCompare compare)
  {
    return ETL_OR_STD::make_pair(etl::lower_bound(first, last, value, compare),
                                 etl::upper_bound(first, last, value, compare));
  }
 
  template<typename TIterator, typename TValue>
  ETL_NODISCARD
  ETL_OR_STD::pair<TIterator, TIterator> equal_range(TIterator first, TIterator last, const TValue& value)
  {
    typedef etl::less<typename etl::iterator_traits<TIterator>::value_type> compare;
 
    return ETL_OR_STD::make_pair(etl::lower_bound(first, last, value, compare()),
                                 etl::upper_bound(first, last, value, compare()));
  }
 
  //***************************************************************************
  // binary_search
  //***************************************************************************
  template <typename TIterator, typename T, typename Compare>
  ETL_NODISCARD
  bool binary_search(TIterator first, TIterator last, const T& value, Compare compare)
  {
    first = etl::lower_bound(first, last, value, compare);
 
    return (!(first == last) && !(compare(value, *first)));
  }
 
  template <typename TIterator, typename T>
  ETL_NODISCARD
  bool binary_search(TIterator first, TIterator last, const T& value)
  {
    typedef etl::less<typename etl::iterator_traits<TIterator>::value_type> compare;
 
    return binary_search(first, last, value, compare());
  }
 
  //***************************************************************************
  // find_if
  //***************************************************************************
  template <typename TIterator, typename TUnaryPredicate>
  ETL_NODISCARD
  ETL_CONSTEXPR14
  TIterator find_if(TIterator first, TIterator last, TUnaryPredicate predicate)
  {
    while (first != last)
    {
      if (predicate(*first))
      {
        return first;
      }
 
      ++first;
    }
 
    return last;
  }
 
  //***************************************************************************
  // find
  //***************************************************************************
  template <typename TIterator, typename T>
  ETL_NODISCARD
  ETL_CONSTEXPR14
  TIterator find(TIterator first, TIterator last, const T& value)
  {
    while (first != last)
    {
      if (*first == value)
      {
        return first;
      }
 
      ++first;
    }
 
    return last;
  }
 
  //***************************************************************************
  // fill
#if ETL_USING_STL && ETL_USING_CPP20
  template<typename TIterator, typename TValue>
  constexpr void fill(TIterator first, TIterator last, const TValue& value)
  {
    std::fill(first, last, value);
  }
#else
  template<typename TIterator, typename TValue>
  ETL_CONSTEXPR14 void fill(TIterator first, TIterator last, const TValue& value)
  {
    while (first != last)
    {
      *first = value;
      ++first;
    }
  }
#endif
 
  //***************************************************************************
  // fill_n
#if ETL_USING_STL && ETL_USING_CPP20
  template<typename TIterator, typename TSize, typename TValue>
  constexpr TIterator fill_n(TIterator first, TSize count, const TValue& value)
  {
    return std::fill_n(first, count, value);
  }
#else
  template<typename TIterator, typename TSize, typename TValue>
  ETL_CONSTEXPR14 TIterator fill_n(TIterator first, TSize count, const TValue& value)
  {
    while (count != 0)
    {
      *first++ = value;
      --count;
    }
 
    return first;
  }
#endif
 
  //***************************************************************************
  // count
  //***************************************************************************
  template <typename TIterator, typename T>
  ETL_NODISCARD
  ETL_CONSTEXPR14
  typename etl::iterator_traits<TIterator>::difference_type count(TIterator first, TIterator last, const T& value)
  {
    typename iterator_traits<TIterator>::difference_type n = 0;
 
    while (first != last)
    {
      if (*first == value)
      {
        ++n;
      }
 
      ++first;
    }
 
    return n;
  }
 
  //***************************************************************************
  // count_if
  //***************************************************************************
  template <typename TIterator, typename TUnaryPredicate>
  ETL_NODISCARD
  ETL_CONSTEXPR14
  typename etl::iterator_traits<TIterator>::difference_type 
    count_if(TIterator first, TIterator last, TUnaryPredicate predicate)
  {
    typename iterator_traits<TIterator>::difference_type n = 0;
 
    while (first != last)
    {
      if (predicate(*first))
      {
        ++n;
      }
 
      ++first;
    }
 
    return n;
  }
 
  //***************************************************************************
  // equal
#if ETL_USING_STL && ETL_USING_CPP20
  // Three parameter
  template <typename TIterator1, typename TIterator2>
  [[nodiscard]]
  constexpr
  bool equal(TIterator1 first1, TIterator1 last1, TIterator2 first2)
  {
    return std::equal(first1, last1, first2);
  }
 
  // Three parameter + predicate
  template <typename TIterator1, typename TIterator2, typename TPredicate>
  [[nodiscard]]
  constexpr
  bool equal(TIterator1 first1, TIterator1 last1, TIterator2 first2, TPredicate predicate)
  {
    return std::equal(first1, last1, first2, predicate);
  }
 
  // Four parameter
  template <typename TIterator1, typename TIterator2>
  [[nodiscard]]
  constexpr
  bool equal(TIterator1 first1, TIterator1 last1, TIterator2 first2, TIterator2 last2)
  {
    return std::equal(first1, last1, first2, last2);
  }
 
  // Four parameter + Predicate
  template <typename TIterator1, typename TIterator2, typename TPredicate>
  [[nodiscard]]
  constexpr
  bool equal(TIterator1 first1, TIterator1 last1, TIterator2 first2, TIterator2 last2, TPredicate predicate)
  {
    return std::equal(first1, last1, first2, last2, predicate);
  }
 
#else
 
  template <typename TIterator1, typename TIterator2>
  ETL_NODISCARD
  ETL_CONSTEXPR14
  bool equal(TIterator1 first1, TIterator1 last1, TIterator2 first2)
  {
    while (first1 != last1)
    {
      if (*first1 != *first2)
      {
        return false;
      }
 
      ++first1;
      ++first2;
    }
 
    return true;
  }
 
  // Predicate
  template <typename TIterator1, typename TIterator2, typename TPredicate>
  ETL_NODISCARD
  ETL_CONSTEXPR14 
  bool equal(TIterator1 first1, TIterator1 last1, TIterator2 first2, TPredicate predicate)
  {
    while (first1 != last1)
    {
      if (!predicate(*first1, *first2))
      {
        return false;
      }
 
      ++first1;
      ++first2;
    }
 
    return true;
  }
 
  // Four parameter
  template <typename TIterator1, typename TIterator2>
  ETL_NODISCARD
  ETL_CONSTEXPR14
  bool equal(TIterator1 first1, TIterator1 last1, TIterator2 first2, TIterator2 last2)
  {
    while ((first1 != last1) && (first2 != last2))
    {
      if (*first1 != *first2)
      {
        return false;
      }
 
      ++first1;
      ++first2;
    }
 
    return (first1 == last1) && (first2 == last2);
  }
 
  // Four parameter, Predicate
  template <typename TIterator1, typename TIterator2, typename TPredicate>
  ETL_NODISCARD
  ETL_CONSTEXPR14
  bool equal(TIterator1 first1, TIterator1 last1, TIterator2 first2, TIterator2 last2, TPredicate predicate)
  {
    while ((first1 != last1) && (first2 != last2))
    {
      if (!predicate(*first1 , *first2))
      {
        return false;
      }
 
      ++first1;
      ++first2;
    }
 
    return (first1 == last1) && (first2 == last2);
  }
#endif
 
  //***************************************************************************
  // lexicographical_compare
  //***************************************************************************
  template <typename TIterator1, typename TIterator2, typename TCompare>
  ETL_NODISCARD
  ETL_CONSTEXPR14
  bool lexicographical_compare(TIterator1 first1, TIterator1 last1,
                               TIterator2 first2, TIterator2 last2,
                               TCompare compare)
  {
    while ((first1 != last1) && (first2 != last2))
    {
      if (compare(*first1, *first2))
      {
        return true;
      }
 
      if (compare(*first2, *first1))
      {
        return false;
      }
 
      ++first1;
      ++first2;
    }
 
    return (first1 == last1) && (first2 != last2);
  }
 
  // lexicographical_compare
  template <typename TIterator1, typename TIterator2>
  ETL_NODISCARD
  ETL_CONSTEXPR14
  bool lexicographical_compare(TIterator1 first1, TIterator1 last1,
                               TIterator2 first2, TIterator2 last2)
  {
    typedef etl::less<typename etl::iterator_traits<TIterator1>::value_type> compare;
 
    return etl::lexicographical_compare(first1, last1, first2, last2, compare());
  }
 
  //***************************************************************************
  // min
  //***************************************************************************
  template <typename T, typename TCompare>
  ETL_NODISCARD
  ETL_CONSTEXPR 
  const T& min(const T& a, const T& b, TCompare compare)
  {
    return (compare(a, b)) ? a : b;
  }
 
  template <typename T>
  ETL_NODISCARD
  ETL_CONSTEXPR 
  const T& min(const T& a, const T& b)
  {
    typedef etl::less<T> compare;
 
    return etl::min(a, b, compare());
  }
 
  //***************************************************************************
  // max
  //***************************************************************************
  template <typename T, typename TCompare>
  ETL_NODISCARD
  ETL_CONSTEXPR 
  const T& max(const T& a, const T& b, TCompare compare)
  {
    return (compare(a, b)) ? b : a;
  }
 
  template <typename T>
  ETL_NODISCARD
  ETL_CONSTEXPR 
  const T& max(const T& a, const T& b)
  {
    typedef etl::less<T> compare;
 
    return etl::max(a, b, compare());
  }
 
  //***************************************************************************
  // for_each
  //***************************************************************************
  template <typename TIterator, typename TUnaryOperation>
  ETL_CONSTEXPR14 
  TUnaryOperation for_each(TIterator first, TIterator last, TUnaryOperation unary_operation)
  {
    while (first != last)
    {
      unary_operation(*first);
      ++first;
    }
 
    return unary_operation;
  }
 
  //***************************************************************************
  // transform
  //***************************************************************************
  template <typename TIteratorIn, typename TIteratorOut, typename TUnaryOperation>
  ETL_CONSTEXPR14
  TIteratorOut transform(TIteratorIn first1, TIteratorIn last1, TIteratorOut d_first, TUnaryOperation unary_operation)
  {
    while (first1 != last1)
    {
      *d_first = unary_operation(*first1);
 
      ++d_first;
      ++first1;
    }
 
    return d_first;
  }
 
  template <typename TIteratorIn1, typename TIteratorIn2, typename TIteratorOut, typename TBinaryOperation>
  ETL_CONSTEXPR14
  TIteratorOut transform(TIteratorIn1 first1, TIteratorIn1 last1, TIteratorIn2 first2, TIteratorOut d_first, TBinaryOperation binary_operation)
  {
    while (first1 != last1)
    {
      *d_first = binary_operation(*first1, *first2);
 
      ++d_first;
      ++first1;
      ++first2;
    }
 
    return d_first;
  }
 
  //***************************************************************************
  // replace
  //***************************************************************************
  template <typename TIterator, typename T>
  ETL_CONSTEXPR14 void replace(TIterator first, TIterator last, const T& old_value, const T& new_value)
  {
    while (first != last)
    {
      if (*first == old_value)
      {
        *first = new_value;
      }
 
      ++first;
    }
  }
 
  //***************************************************************************
  // replace_if
  //***************************************************************************
  template <typename TIterator, typename TPredicate, typename T>
  ETL_CONSTEXPR14 void replace_if(TIterator first, TIterator last, TPredicate predicate, const T& new_value)
  {
    while (first != last)
    {
      if (predicate(*first))
      {
        *first = new_value;
      }
 
      ++first;
    }
  }
 
  //***************************************************************************
  // Heap
  //***************************************************************************
  namespace private_heap
  {
    // Push Heap Helper
    template <typename TIterator, typename TDistance, typename TValue, typename TCompare>
    void push_heap(TIterator first, TDistance value_index, TDistance top_index, TValue value, TCompare compare)
    {
      TDistance parent = (value_index - 1) / 2;
 
      while ((value_index > top_index) && compare(first[parent], value))
      {
        first[value_index] = ETL_MOVE(first[parent]);
        value_index = parent;
        parent = (value_index - 1) / 2;
      }
 
      first[value_index] = ETL_MOVE(value);
    }
 
    // Adjust Heap Helper
    template <typename TIterator, typename TDistance, typename TValue, typename TCompare>
    void adjust_heap(TIterator first, TDistance value_index, TDistance length, TValue value, TCompare compare)
    {
      TDistance top_index = value_index;
      TDistance child2nd = (2 * value_index) + 2;
 
      while (child2nd < length)
      {
        if (compare(first[child2nd], first[child2nd - 1]))
        {
          --child2nd;
        }
 
        first[value_index] = ETL_MOVE(first[child2nd]);
        value_index = child2nd;
        child2nd = 2 * (child2nd + 1);
      }
 
      if (child2nd == length)
      {
        first[value_index] = ETL_MOVE(first[child2nd - 1]);
        value_index = child2nd - 1;
      }
 
      push_heap(first, value_index, top_index, ETL_MOVE(value), compare);
    }
 
    // Is Heap Helper
    template <typename TIterator, typename TDistance, typename TCompare>
    bool is_heap(const TIterator first, const TDistance n, TCompare compare)
    {
      TDistance parent = 0;
 
      for (TDistance child = 1; child < n; ++child)
      {
        if (compare(first[parent], first[child]))
        {
          return false;
        }
 
        if ((child & 1) == 0)
        {
          ++parent;
        }
      }
 
      return true;
    }
  }
 
  // Pop Heap
  template <typename TIterator, typename TCompare>
  void pop_heap(TIterator first, TIterator last, TCompare compare)
  {
    typedef typename etl::iterator_traits<TIterator>::value_type value_t;
    typedef typename etl::iterator_traits<TIterator>::difference_type distance_t;
 
    value_t value = ETL_MOVE(last[-1]);
    last[-1] = ETL_MOVE(first[0]);
 
    private_heap::adjust_heap(first, distance_t(0), distance_t(last - first - 1), ETL_MOVE(value), compare);
  }
 
  // Pop Heap
  template <typename TIterator>
  void pop_heap(TIterator first, TIterator last)
  {
    typedef etl::less<typename etl::iterator_traits<TIterator>::value_type> compare;
 
    etl::pop_heap(first, last, compare());
  }
 
  // Push Heap
  template <typename TIterator, typename TCompare>
  void push_heap(TIterator first, TIterator last, TCompare compare)
  {
    typedef typename etl::iterator_traits<TIterator>::difference_type difference_t;
    typedef typename etl::iterator_traits<TIterator>::value_type      value_t;
 
    private_heap::push_heap(first, difference_t(last - first - 1), difference_t(0), value_t(ETL_MOVE(*(last - 1))), compare);
  }
 
  // Push Heap
  template <typename TIterator>
  void push_heap(TIterator first, TIterator last)
  {
    typedef etl::less<typename etl::iterator_traits<TIterator>::value_type> compare;
 
    etl::push_heap(first, last, compare());
  }
 
  // Make Heap
  template <typename TIterator, typename TCompare>
  void make_heap(TIterator first, TIterator last, TCompare compare)
  {
    typedef typename etl::iterator_traits<TIterator>::difference_type difference_t;
 
    if ((last - first) < 2)
    {
      return;
    }
 
    difference_t length = last - first;
    difference_t parent = (length - 2) / 2;
 
    while (true)
    {
      private_heap::adjust_heap(first, parent, length, ETL_MOVE(*(first + parent)), compare);
 
      if (parent == 0)
      {
        return;
      }
 
      --parent;
    }
  }
 
  // Make Heap
  template <typename TIterator>
  void make_heap(TIterator first, TIterator last)
  {
    typedef etl::less<typename etl::iterator_traits<TIterator>::value_type> compare;
 
    etl::make_heap(first, last, compare());
  }
 
  // Is Heap
  template <typename TIterator>
  ETL_NODISCARD
    bool is_heap(TIterator first, TIterator last)
  {
    typedef etl::less<typename etl::iterator_traits<TIterator>::value_type> compare;
 
    return private_heap::is_heap(first, last - first, compare());
  }
 
  // Is Heap
  template <typename TIterator, typename TCompare>
  ETL_NODISCARD
  bool is_heap(TIterator first, TIterator last, TCompare compare)
  {
    return private_heap::is_heap(first, last - first, compare);
  }
 
  // Sort Heap
  template <typename TIterator>
  void sort_heap(TIterator first, TIterator last)
  {
    while (first != last)
    {
      etl::pop_heap(first, last);
      --last;
    }
  }
 
  // Sort Heap
  template <typename TIterator, typename TCompare>
  void sort_heap(TIterator first, TIterator last, TCompare compare)
  {
    while (first != last)
    {
      etl::pop_heap(first, last, compare);
      --last;
    }
  }
 
  //***************************************************************************
  // Search
  //***************************************************************************
  template<typename TIterator1, typename TIterator2, typename TCompare>
  ETL_NODISCARD
  ETL_CONSTEXPR14
  TIterator1 search(TIterator1 first, TIterator1 last, TIterator2 search_first, TIterator2 search_last, TCompare compare)
  {
    while (true)
    {
      TIterator1 itr = first;
      TIterator2 search_itr = search_first;
 
      while (true)
      {
        if (search_itr == search_last)
        {
          return first;
        }
 
        if (itr == last)
        {
          return last;
        }
 
        if (!compare(*itr, *search_itr))
        {
          break;
        }
 
        ++itr;
        ++search_itr;
      }
 
      ++first;
    }
  }
 
  // Search
  template<typename TIterator1, typename TIterator2>
  ETL_NODISCARD
  ETL_CONSTEXPR14
  TIterator1 search(TIterator1 first, TIterator1 last, TIterator2 search_first, TIterator2 search_last)
  {
    typedef etl::equal_to<typename etl::iterator_traits<TIterator1>::value_type> compare;
 
    return etl::search(first, last, search_first, search_last, compare());
  }
 
  //***************************************************************************
  // Rotate
  //***************************************************************************
  namespace private_algorithm
  {
#if ETL_USING_CPP11
    //*********************************
    // For random access iterators
    template <typename TIterator>
    ETL_CONSTEXPR14
    typename etl::enable_if<etl::is_random_access_iterator<TIterator>::value, TIterator>::type
      rotate_general(TIterator first, TIterator middle, TIterator last) 
    {
      if (first == middle || middle == last)
      {
        return first;
      }
 
      typedef typename etl::iterator_traits<TIterator>::value_type value_type;
 
      int n = last - first;
      int m = middle - first;
      int gcd_nm = (n == 0 || m == 0) ? n + m : etl::gcd(n, m);
 
      TIterator result = first + (last - middle);
 
      for (int i = 0; i < gcd_nm; i++) 
      {
        value_type temp = ETL_MOVE(*(first + i));
        int j = i;
        
        while (true) 
        {
          int k = j + m;
          
          if (k >= n)
          {
            k = k - n;
          }
          
          if (k == i)
          {
            break;
          }
 
          *(first + j) = ETL_MOVE(*(first + k));
          j = k;
        }
 
        *(first + j) = ETL_MOVE(temp);
      }
 
      return result;
    }
#else
    //*********************************
    // For random access iterators
    template <typename TIterator>
    ETL_CONSTEXPR14
    typename etl::enable_if<etl::is_random_access_iterator<TIterator>::value, TIterator>::type
      rotate_general(TIterator first, TIterator middle, TIterator last)
    {
      if (first == middle || middle == last)
      {
        return first;
      }
 
      typedef typename etl::iterator_traits<TIterator>::value_type value_type;
 
      int n = last - first;
      int m = middle - first;
      int gcd_nm = (n == 0 || m == 0) ? n + m : etl::gcd(n, m);
 
      TIterator result = first + (last - middle);
 
      for (int i = 0; i < gcd_nm; i++)
      {
        value_type temp = *(first + i);
        int j = i;
 
        while (true)
        {
          int k = j + m;
 
          if (k >= n)
          {
            k = k - n;
          }
 
          if (k == i)
          {
            break;
          }
 
          *(first + j) = *(first + k);
          j = k;
        }
 
        *(first + j) = temp;
      }
 
      return result;
    }
#endif
 
    //*********************************
    // For bidirectional iterators
    template <typename TIterator>
    ETL_CONSTEXPR14
    typename etl::enable_if<etl::is_bidirectional_iterator<TIterator>::value, TIterator>::type
      rotate_general(TIterator first, TIterator middle, TIterator last)
    {
      if (first == middle || middle == last)
      {
        return first;
      }
 
      TIterator result = first;
      etl::advance(result, etl::distance(middle, last));
 
      reverse(first, middle);
      reverse(middle, last);
      reverse(first, last);
 
      return result;
    }
 
    //*********************************
    // For forward iterators
    template <typename TIterator>
    ETL_CONSTEXPR14
    typename etl::enable_if<etl::is_forward_iterator<TIterator>::value, TIterator>::type
      rotate_general(TIterator first, TIterator middle, TIterator last)
    {
      if (first == middle || middle == last)
      {
        return first;
      }
 
      TIterator next = middle;
      TIterator result = first;
      etl::advance(result, etl::distance(middle, last));
 
      while (first != next)
      {
        using ETL_OR_STD::swap;
        swap(*first++, *next++);
 
        if (next == last)
        {
          next = middle;
        }
        else if (first == middle)
        {
          middle = next;
        }
      }
 
      return result;
    }
 
    //*********************************
    // Simplified algorithm for rotate left by one
    template <typename TIterator>
    ETL_CONSTEXPR14
    TIterator rotate_left_by_one(TIterator first, TIterator last)
    {
      typedef typename etl::iterator_traits<TIterator>::value_type value_type;
 
      // Save the first item.
      value_type temp(ETL_MOVE(*first));
 
      // Move the rest.
      TIterator result = etl::move(etl::next(first), last, first);
 
      // Restore the first item in its rotated position.
      *result = ETL_MOVE(temp);
 
      // The new position of the first item.
      return result;
    }
 
    //*********************************
    // Simplified for algorithm rotate right by one
    template <typename TIterator>
    ETL_CONSTEXPR14
    TIterator rotate_right_by_one(TIterator first, TIterator last)
    {
      typedef typename etl::iterator_traits<TIterator>::value_type value_type;
 
      // Save the last item.
      TIterator previous = etl::prev(last);
      value_type temp(ETL_MOVE(*previous));
 
      // Move the rest.
      TIterator result = etl::move_backward(first, previous, last);
 
      // Restore the last item in its rotated position.
      *first = ETL_MOVE(temp);
 
      // The new position of the first item.
      return result;
    }
  }
 
  //*********************************
  template<typename TIterator>
  ETL_CONSTEXPR14
  TIterator rotate(TIterator first, TIterator middle, TIterator last)
  {
    if (etl::next(first) == middle)
    {
      return private_algorithm::rotate_left_by_one(first, last);
    }
 
    if (etl::next(middle) == last)
    {
#if ETL_USING_CPP20
      if ETL_IF_CONSTEXPR(etl::is_forward_iterator<TIterator>::value)
      {
        return private_algorithm::rotate_general(first, middle, last);
      }
      else
      {
        return private_algorithm::rotate_right_by_one(first, last);
      }
#else
      return private_algorithm::rotate_general(first, middle, last);
#endif
    }
 
    return private_algorithm::rotate_general(first, middle, last);
  }
 
  //***************************************************************************
  // find_end
  //***************************************************************************
  // Predicate
  template <typename TIterator1, typename TIterator2, typename TPredicate>
  ETL_NODISCARD
  ETL_CONSTEXPR14
  TIterator1 find_end(TIterator1 b, TIterator1 e,
                      TIterator2 sb, TIterator2 se,
                      TPredicate predicate)
  {
    if (sb == se)
    {
      return e;
    }
 
    TIterator1 result = e;
 
    while (true)
    {
      TIterator1 new_result = etl::search(b, e, sb, se, predicate);
 
      if (new_result == e)
      {
        break;
      }
      else
      {
        result = new_result;
        b = result;
        ++b;
      }
    }
    return result;
  }
 
  // Default
  template <typename TIterator1, typename TIterator2>
  ETL_NODISCARD
  ETL_CONSTEXPR14
  TIterator1 find_end(TIterator1 b, TIterator1 e,
                      TIterator2 sb, TIterator2 se)
  {
    typedef etl::equal_to<typename etl::iterator_traits<TIterator1>::value_type> predicate;
 
    return find_end(b, e, sb, se, predicate());
  }
 
  //***************************************************************************
  //***************************************************************************
  template <typename TIterator, typename TCompare>
  ETL_NODISCARD
  ETL_CONSTEXPR14
  TIterator min_element(TIterator begin,
                        TIterator end,
                        TCompare  compare)
  {
    TIterator minimum = begin;
 
    if (begin != end)
    {
      ++begin;
 
      while (begin != end)
      {
        if (compare(*begin, *minimum))
        {
          minimum = begin;
        }
 
        ++begin;
      }
    }
 
    return minimum;
  }
 
  //***************************************************************************
  //***************************************************************************
  template <typename TIterator>
  ETL_NODISCARD
  ETL_CONSTEXPR14
  TIterator min_element(TIterator begin,
                        TIterator end)
  {
    typedef typename etl::iterator_traits<TIterator>::value_type value_t;
 
    return etl::min_element(begin, end, etl::less<value_t>());
  }
 
  //***************************************************************************
  //***************************************************************************
  template <typename TIterator, typename TCompare>
  ETL_NODISCARD
  ETL_CONSTEXPR14
  TIterator max_element(TIterator begin,
                        TIterator end,
                        TCompare  compare)
  {
    TIterator maximum = begin;
 
    if (begin != end)
    {
      ++begin;
 
      while (begin != end)
      {
        if (!compare(*begin, *maximum))
        {
          maximum = begin;
        }
 
        ++begin;
      }
    }
 
    return maximum;
  }
 
  //***************************************************************************
  //***************************************************************************
  template <typename TIterator>
  ETL_NODISCARD
  ETL_CONSTEXPR14
  TIterator max_element(TIterator begin,
                        TIterator end)
  {
    typedef typename etl::iterator_traits<TIterator>::value_type value_t;
 
    return etl::max_element(begin, end, etl::less<value_t>());
  }
 
  //***************************************************************************
  //***************************************************************************
  template <typename TIterator, typename TCompare>
  ETL_NODISCARD
  ETL_CONSTEXPR14
  ETL_OR_STD::pair<TIterator, TIterator> minmax_element(TIterator begin,
                                                        TIterator end,
                                                        TCompare  compare)
  {
    TIterator minimum = begin;
    TIterator maximum = begin;
 
    if (begin != end)
    {
      ++begin;
 
      while (begin != end)
      {
        if (compare(*begin, *minimum))
        {
          minimum = begin;
        }
 
        if (compare(*maximum, *begin))
        {
          maximum = begin;
        }
 
        ++begin;
      }
    }
 
    return ETL_OR_STD::pair<TIterator, TIterator>(minimum, maximum);
  }
 
  //***************************************************************************
  //***************************************************************************
  template <typename TIterator>
  ETL_NODISCARD
  ETL_CONSTEXPR14
  ETL_OR_STD::pair<TIterator, TIterator> minmax_element(TIterator begin,
                                                        TIterator end)
  {
    typedef typename etl::iterator_traits<TIterator>::value_type value_t;
 
    return etl::minmax_element(begin, end, etl::less<value_t>());
  }
 
  //***************************************************************************
  //***************************************************************************
  template <typename T>
  ETL_NODISCARD
  ETL_CONSTEXPR14
  ETL_OR_STD::pair<const T&, const T&> minmax(const T& a,
                                              const T& b)
  {
    return (b < a) ? ETL_OR_STD::pair<const T&, const T&>(b, a) : ETL_OR_STD::pair<const T&, const T&>(a, b);
  }
 
  //***************************************************************************
  //***************************************************************************
  template <typename T, typename TCompare>
  ETL_NODISCARD
  ETL_CONSTEXPR14
  ETL_OR_STD::pair<const T&, const T&> minmax(const T& a,
                                              const T& b,
                                              TCompare compare)
  {
    return compare(b, a) ? ETL_OR_STD::pair<const T&, const T&>(b, a) : ETL_OR_STD::pair<const T&, const T&>(a, b);
  }
 
  //***************************************************************************
  //***************************************************************************
  template <typename TIterator>
  ETL_NODISCARD
  ETL_CONSTEXPR14
  TIterator is_sorted_until(TIterator begin,
                            TIterator end)
  {
    if (begin != end)
    {
      TIterator next = begin;
 
      while (++next != end)
      {
        if (*next < *begin)
        {
          return next;
        }
 
        ++begin;
      }
    }
 
    return end;
  }
 
  //***************************************************************************
  //***************************************************************************
  template <typename TIterator, typename TCompare>
  ETL_NODISCARD
  ETL_CONSTEXPR14
  TIterator is_sorted_until(TIterator begin,
                            TIterator end,
                            TCompare  compare)
  {
    if (begin != end)
    {
      TIterator next = begin;
 
      while (++next != end)
      {
        if (compare(*next, *begin))
        {
          return next;
        }
 
        ++begin;
      }
    }
 
    return end;
  }
 
  //***************************************************************************
  //***************************************************************************
  template<typename TIterator>
  ETL_NODISCARD
  ETL_CONSTEXPR14
  bool is_sorted(TIterator begin,
                 TIterator end)
  {
    return etl::is_sorted_until(begin, end) == end;
  }
 
  //***************************************************************************
  //***************************************************************************
  template<typename TIterator, typename TCompare>
  ETL_NODISCARD
  ETL_CONSTEXPR14
  bool is_sorted(TIterator begin,
                 TIterator end,
                 TCompare  compare)
  {
    return etl::is_sorted_until(begin, end, compare) == end;
  }
 
  //***************************************************************************
  //***************************************************************************
  template <typename TIterator, typename TCompare>
  ETL_NODISCARD
  ETL_CONSTEXPR14
  TIterator is_unique_sorted_until(TIterator begin,
                                   TIterator end,
                                   TCompare  compare)
  {
    if (begin != end)
    {
      TIterator next = begin;
 
      while (++next != end)
      {
        if (!compare(*begin, *next))
        {
          return next;
        }
 
        ++begin;
      }
    }
 
    return end;
  }
 
  //***************************************************************************
  //***************************************************************************
  template <typename TIterator>
  ETL_NODISCARD
  ETL_CONSTEXPR14
  TIterator is_unique_sorted_until(TIterator begin,
                                   TIterator end)
  {
    if (begin != end)
    {
      TIterator next = begin;
 
      while (++next != end)
      {
        if (!(*begin < *next))
        {
          return next;
        }
 
        ++begin;
      }
    }
 
    return end;
  }
 
  //***************************************************************************
  //***************************************************************************
  template<typename TIterator>
  ETL_NODISCARD
  ETL_CONSTEXPR14
  bool is_unique_sorted(TIterator begin,
                        TIterator end)
  {
    return etl::is_unique_sorted_until(begin, end) == end;
  }
 
  //***************************************************************************
  //***************************************************************************
  template<typename TIterator, typename TCompare>
  ETL_NODISCARD
    ETL_CONSTEXPR14
    bool is_unique_sorted(TIterator begin,
                          TIterator end,
                          TCompare  compare)
  {
    return etl::is_unique_sorted_until(begin, end, compare) == end;
  }
 
  //***************************************************************************
  //***************************************************************************
  template <typename TIterator, typename TUnaryPredicate>
  ETL_NODISCARD
  ETL_CONSTEXPR14
  TIterator find_if_not(TIterator       begin,
                        TIterator       end,
                        TUnaryPredicate predicate)
  {
    while (begin != end)
    {
      if (!predicate(*begin))
      {
        return begin;
      }
 
      ++begin;
    }
 
    return end;
  }
 
  //***************************************************************************
  //***************************************************************************
  template <typename TIterator1, typename TIterator2>
  ETL_NODISCARD
  ETL_CONSTEXPR14
  bool is_permutation(TIterator1 begin1,
                      TIterator1 end1,
                      TIterator2 begin2)
  {
    if (begin1 != end1)
    {
      TIterator2 end2 = begin2;
 
      etl::advance(end2, etl::distance(begin1, end1));
 
      for (TIterator1 i = begin1; i != end1; ++i)
      {
        if (i == etl::find(begin1, i, *i))
        {
          size_t n = etl::count(begin2, end2, *i);
 
          if (n == 0 || size_t(etl::count(i, end1, *i)) != n)
          {
            return false;
          }
        }
      }
    }
 
    return true;
  }
 
  //***************************************************************************
  //***************************************************************************
  template <typename TIterator1, typename TIterator2, typename TBinaryPredicate>
  ETL_NODISCARD
  ETL_CONSTEXPR14
  bool is_permutation(TIterator1       begin1,
                      TIterator1       end1,
                      TIterator2       begin2,
                      TBinaryPredicate predicate)
  {
    if (begin1 != end1)
    {
      TIterator2 end2 = begin2;
 
      etl::advance(end2, etl::distance(begin1, end1));
 
      for (TIterator1 i = begin1; i != end1; ++i)
      {
        if (i == etl::find_if(begin1, i, etl::bind1st(predicate, *i)))
        {
          size_t n = etl::count(begin2, end2, *i);
 
          if (n == 0 || size_t(etl::count(i, end1, *i)) != n)
          {
            return false;
          }
        }
      }
    }
 
    return true;
  }
 
  //***************************************************************************
  //***************************************************************************
  template <typename TIterator1, typename TIterator2>
  ETL_NODISCARD
  ETL_CONSTEXPR14
  bool is_permutation(TIterator1 begin1,
                      TIterator1 end1,
                      TIterator2 begin2,
                      TIterator2 end2)
  {
    if (begin1 != end1)
    {
      for (TIterator1 i = begin1; i != end1; ++i)
      {
        if (i == etl::find(begin1, i, *i))
        {
          size_t n = etl::count(begin2, end2, *i);
 
          if (n == 0 || size_t(etl::count(i, end1, *i)) != n)
          {
            return false;
          }
        }
      }
    }
 
    return true;
  }
 
  //***************************************************************************
  //***************************************************************************
  template <typename TIterator1, typename TIterator2, typename TBinaryPredicate>
  ETL_NODISCARD
  bool is_permutation(TIterator1       begin1,
                      TIterator1       end1,
                      TIterator2       begin2,
                      TIterator2       end2,
                      TBinaryPredicate predicate)
  {
    if (begin1 != end1)
    {
      for (TIterator1 i = begin1; i != end1; ++i)
      {
        if (i == etl::find_if(begin1, i, etl::bind1st(predicate, *i)))
        {
          size_t n = etl::count(begin2, end2, *i);
 
          if (n == 0 || size_t(etl::count(i, end1, *i)) != n)
          {
            return false;
          }
        }
      }
    }
 
    return true;
  }
 
  //***************************************************************************
  //***************************************************************************
  template <typename TIterator, typename TUnaryPredicate>
  ETL_NODISCARD
  ETL_CONSTEXPR14
  bool is_partitioned(TIterator       begin,
                      TIterator       end,
                      TUnaryPredicate predicate)
  {
    while (begin != end)
    {
      if (!predicate(*begin))
      {
        break;
      }
 
      ++begin;
    }
 
    while (begin != end)
    {
      if (predicate(*begin))
      {
        return false;
      }
 
      ++begin;
    }
 
    return true;
  }
 
  //***************************************************************************
  //***************************************************************************
  template <typename TIterator, typename TUnaryPredicate>
  ETL_NODISCARD
  ETL_CONSTEXPR14
  TIterator partition_point(TIterator       begin,
                            TIterator       end,
                            TUnaryPredicate predicate)
  {
    while (begin != end)
    {
      if (!predicate(*begin))
      {
        return begin;
      }
 
      ++begin;
    }
 
    return begin;
  }
 
  //***************************************************************************
  //***************************************************************************
  template <typename TSource, typename TDestinationTrue, typename TDestinationFalse, typename TUnaryPredicate>
  ETL_CONSTEXPR14
  ETL_OR_STD::pair<TDestinationTrue, TDestinationFalse> partition_copy(TSource           begin,
                                                                       TSource           end,
                                                                       TDestinationTrue  destination_true,
                                                                       TDestinationFalse destination_false,
                                                                       TUnaryPredicate   predicate)
  {
    while (begin != end)
    {
      if (predicate(*begin))
      {
        *destination_true = *begin;
        ++destination_true;
      }
      else
      {
        *destination_false = *begin;
        ++destination_false;
      }
 
      ++begin;
    }
 
    return ETL_OR_STD::pair<TDestinationTrue, TDestinationFalse>(destination_true, destination_false);
  }
 
  //***************************************************************************
  //***************************************************************************
  template <typename TIterator, typename TOutputIterator, typename TUnaryPredicate>
  ETL_CONSTEXPR14
  TOutputIterator copy_if(TIterator       begin,
                          TIterator       end,
                          TOutputIterator out,
                          TUnaryPredicate predicate)
  {
    while (begin != end)
    {
      if (predicate(*begin))
      {
        *out = *begin;
        ++out;
      }
 
      ++begin;
    }
 
    return out;
  }
 
  //***************************************************************************
  //***************************************************************************
  template <typename TIterator, typename TUnaryPredicate>
  ETL_NODISCARD
  ETL_CONSTEXPR14
  bool all_of(TIterator       begin,
              TIterator       end,
              TUnaryPredicate predicate)
  {
    return etl::find_if_not(begin, end, predicate) == end;
  }
 
  //***************************************************************************
  //***************************************************************************
  template <typename TIterator, typename TUnaryPredicate>
  ETL_NODISCARD
  ETL_CONSTEXPR14
  bool any_of(TIterator       begin,
              TIterator       end,
              TUnaryPredicate predicate)
  {
    return etl::find_if(begin, end, predicate) != end;
  }
 
  //***************************************************************************
  //***************************************************************************
  template <typename TIterator, typename TUnaryPredicate>
  ETL_NODISCARD
  ETL_CONSTEXPR14
  bool none_of(TIterator       begin,
               TIterator       end,
               TUnaryPredicate predicate)
  {
    return etl::find_if(begin, end, predicate) == end;
  }
 
#if ETL_NOT_USING_STL
  //***************************************************************************
  //***************************************************************************
  template <typename TIterator, typename TCompare>
  void sort(TIterator first, TIterator last, TCompare compare)
  {
    etl::shell_sort(first, last, compare);
  }
 
  //***************************************************************************
  //***************************************************************************
  template <typename TIterator>
  void sort(TIterator first, TIterator last)
  {
    etl::shell_sort(first, last, etl::less<typename etl::iterator_traits<TIterator>::value_type>());
  }
 
  //***************************************************************************
  //***************************************************************************
  template <typename TIterator, typename TCompare>
  void stable_sort(TIterator first, TIterator last, TCompare compare)
  {
    etl::insertion_sort(first, last, compare);
  }
 
  //***************************************************************************
  //***************************************************************************
  template <typename TIterator>
  void stable_sort(TIterator first, TIterator last)
  {
    etl::insertion_sort(first, last, etl::less<typename etl::iterator_traits<TIterator>::value_type>());
  }
#else
  //***************************************************************************
  //***************************************************************************
  template <typename TIterator, typename TCompare>
  void sort(TIterator first, TIterator last, TCompare compare)
  {
    std::sort(first, last, compare);
  }
 
  //***************************************************************************
  //***************************************************************************
  template <typename TIterator>
  void sort(TIterator first, TIterator last)
  {
    std::sort(first, last);
  }
 
  //***************************************************************************
  //***************************************************************************
  template <typename TIterator, typename TCompare>
  void stable_sort(TIterator first, TIterator last, TCompare compare)
  {
    std::stable_sort(first, last, compare);
  }
 
  //***************************************************************************
  //***************************************************************************
  template <typename TIterator>
  void stable_sort(TIterator first, TIterator last)
  {
    std::stable_sort(first, last);
  }
#endif
 
  //***************************************************************************
  //***************************************************************************
  template <typename TIterator, typename T>
  ETL_CONSTEXPR14 
  T accumulate(TIterator first, TIterator last, T sum)
  {
    while (first != last)
    {
      sum = ETL_MOVE(sum) + *first;
      ++first;
    }
      
    return sum;
  }
 
  //***************************************************************************
  //***************************************************************************
  template <typename TIterator, typename T, typename TBinaryOperation>
  ETL_CONSTEXPR14 
  T accumulate(TIterator first, TIterator last, T sum, TBinaryOperation operation)
  {
    while (first != last)
    {
      sum = operation(ETL_MOVE(sum), *first);
      ++first;
    }
 
    return sum;
  }
 
  //***************************************************************************
  //***************************************************************************
  template<typename T, typename TCompare>
  ETL_CONSTEXPR
  T clamp(const T& value, const T& low, const T& high, TCompare compare)
  {
    return compare(value, low) ? low : compare(high, value) ? high : value;
  }
  
  template <typename T>
  ETL_CONSTEXPR
  T clamp(const T& value, const T& low, const T& high)
  {
    return clamp(value, low, high, etl::less<T>());
  }
 
  template<typename T, T Low, T High, typename TCompare>
  ETL_CONSTEXPR
  T clamp(const T& value, TCompare compare)
  {
    return compare(value, Low) ? Low : compare(High, value) ? High : value;
  }
 
  template <typename T, T Low, T High>
  ETL_CONSTEXPR
  T clamp(const T& value)
  {
    return clamp<T, Low, High>(value, etl::less<T>());
  }
 
  //***************************************************************************
  //***************************************************************************
  template <typename TIterator, typename T>
  ETL_CONSTEXPR14
  TIterator remove(TIterator first, TIterator last, const T& value)
  {    
    first = etl::find(first, last, value);
 
    if (first != last)
    {
      TIterator itr = first;
 
      while (++itr != last)
      {
        if (!(*itr == value))
        {
          *first++ = ETL_MOVE(*itr);
        }
      }
    }
      
    return first;
  }
 
  //***************************************************************************
  //***************************************************************************
  template <typename TIterator, typename TUnaryPredicate>
  ETL_CONSTEXPR14
  TIterator remove_if(TIterator first, TIterator last, TUnaryPredicate predicate)
  {
    first = etl::find_if(first, last, predicate);
 
    if (first != last)
    {
      TIterator itr = first;
 
      while (++itr != last)
      {
        if (!predicate(*itr))
        {
          *first++ = ETL_MOVE(*itr);
        }
      }
    }
 
    return first; 
  }
}
 
//*****************************************************************************
// ETL extensions to the STL algorithms.
//*****************************************************************************
namespace etl
{
  //***************************************************************************
  //***************************************************************************
  template <typename TInputIterator,
            typename TOutputIterator>
  ETL_CONSTEXPR14
  typename etl::enable_if<etl::is_random_iterator<TInputIterator>::value &&
                          etl::is_random_iterator<TOutputIterator>::value, TOutputIterator>::type
    copy_s(TInputIterator  i_begin,
           TInputIterator  i_end,
           TOutputIterator o_begin,
           TOutputIterator o_end)
  {
    typedef typename iterator_traits<TInputIterator>::difference_type  s_size_type;
    typedef typename iterator_traits<TOutputIterator>::difference_type d_size_type;
 
#if ETL_USING_CPP11
    typedef typename etl::common_type<s_size_type, d_size_type>::type  min_size_type;
#else
    typedef typename etl::largest_type<s_size_type, d_size_type>::type  min_size_type;
#endif
 
    s_size_type s_size     = etl::distance(i_begin, i_end);
    d_size_type d_size     = etl::distance(o_begin, o_end);
    min_size_type min_size = etl::min<min_size_type>(s_size, d_size);
 
    return etl::copy(i_begin, i_begin + min_size, o_begin);
  }
 
  //***************************************************************************
  //***************************************************************************
  template <typename TInputIterator,
            typename TOutputIterator>
  ETL_CONSTEXPR14
  typename etl::enable_if<!etl::is_random_iterator<TInputIterator>::value ||
                          !etl::is_random_iterator<TOutputIterator>::value, TOutputIterator>::type
   copy_s(TInputIterator  i_begin,
          TInputIterator  i_end,
          TOutputIterator o_begin,
          TOutputIterator o_end)
  {
    while ((i_begin != i_end) && (o_begin != o_end))
    {
      *o_begin = *i_begin;
      ++o_begin;
      ++i_begin;
    }
 
    return o_begin;
  }
 
  //***************************************************************************
  //***************************************************************************
  template <typename TInputIterator,
            typename TSize,
            typename TOutputIterator>
  ETL_CONSTEXPR14
  TOutputIterator copy_n_s(TInputIterator  i_begin,
                           TSize           n,
                           TOutputIterator o_begin,
                           TOutputIterator o_end)
  {
    while ((n-- > 0) && (o_begin != o_end))
    {
      *o_begin = *i_begin;
      ++o_begin;
      ++i_begin;
    }
 
    return o_begin;
  }
 
  //***************************************************************************
  //***************************************************************************
  template <typename TInputIterator,
            typename TSize1,
            typename TOutputIterator,
            typename TSize2>
  ETL_CONSTEXPR14
  TOutputIterator copy_n_s(TInputIterator  i_begin,
                           TSize1          n1,
                           TOutputIterator o_begin,
                           TSize2          n2)
  {
    while ((n1-- > 0) && (n2-- > 0))
    {
      *o_begin = *i_begin;
      ++o_begin;
      ++i_begin;
    }
 
    return o_begin;
  }
 
  //***************************************************************************
  //***************************************************************************
  template <typename TInputIterator,
            typename TOutputIterator,
            typename TUnaryPredicate>
  ETL_CONSTEXPR14
  TOutputIterator copy_if_s(TInputIterator  i_begin,
                            TInputIterator  i_end,
                            TOutputIterator o_begin,
                            TOutputIterator o_end,
                            TUnaryPredicate predicate)
  {
    while ((i_begin != i_end) && (o_begin != o_end))
    {
      if (predicate(*i_begin))
      {
        *o_begin = *i_begin;
        ++o_begin;
      }
 
      ++i_begin;
    }
 
    return o_begin;
  }
 
  //***************************************************************************
    //***************************************************************************
  template <typename TInputIterator,
            typename TSize,
            typename TOutputIterator,
            typename TUnaryPredicate>
  ETL_CONSTEXPR14
  TOutputIterator copy_n_if(TInputIterator  i_begin,
                            TSize           n,
                            TOutputIterator o_begin,
                            TUnaryPredicate predicate)
  {
    while (n-- > 0)
    {
      if (predicate(*i_begin))
      {
        *o_begin = *i_begin;
        ++o_begin;
      }
 
      ++i_begin;
    }
 
    return o_begin;
  }
 
#if ETL_USING_CPP11
  //***************************************************************************
  //***************************************************************************
  template <typename TInputIterator, typename TOutputIterator>
  ETL_CONSTEXPR14
  typename etl::enable_if<etl::is_random_iterator<TInputIterator>::value &&
                          etl::is_random_iterator<TOutputIterator>::value, TOutputIterator>::type
  move_s(TInputIterator  i_begin,
         TInputIterator  i_end,
         TOutputIterator o_begin,
         TOutputIterator o_end)
  {
    using s_size_type = typename iterator_traits<TInputIterator>::difference_type;
    using d_size_type = typename iterator_traits<TOutputIterator>::difference_type;
    using min_size_type = typename etl::common_type<s_size_type, d_size_type>::type;
 
    s_size_type s_size     = etl::distance(i_begin, i_end);
    d_size_type d_size     = etl::distance(o_begin, o_end);
    min_size_type min_size = etl::min<min_size_type>(s_size, d_size);
 
    return etl::move(i_begin, i_begin + min_size, o_begin);
  }
 
  //***************************************************************************
  //***************************************************************************
  template <typename TInputIterator, typename TOutputIterator>
  ETL_CONSTEXPR14
  typename etl::enable_if<!etl::is_random_iterator<TInputIterator>::value ||
                          !etl::is_random_iterator<TOutputIterator>::value, TOutputIterator>::type
  move_s(TInputIterator  i_begin,
         TInputIterator  i_end,
         TOutputIterator o_begin,
         TOutputIterator o_end)
  {
    while ((i_begin != i_end) && (o_begin != o_end))
    {
      *o_begin = etl::move(*i_begin);
      ++i_begin;
      ++o_begin;
    }
 
    return o_begin;
  }
#else
  //***************************************************************************
  //***************************************************************************
  template <typename TInputIterator, typename TOutputIterator>
  TOutputIterator move_s(TInputIterator  i_begin,
                         TInputIterator  i_end,
                         TOutputIterator o_begin,
                         TOutputIterator o_end)
  {
    // Move not supported. Defer to copy.
    return etl::copy_s(i_begin, i_end, o_begin, o_end);
  }
#endif
 
  //***************************************************************************
  //***************************************************************************
  template <typename TIterator, typename TValue>
  ETL_NODISCARD
  ETL_CONSTEXPR14
  TIterator binary_find(TIterator     begin,
                        TIterator     end,
                        const TValue& value)
  {
    TIterator it = etl::lower_bound(begin, end, value);
 
    if ((it == end) || (*it != value))
    {
      it = end;
    }
 
    return it;
  }
 
  //***************************************************************************
  //***************************************************************************
  template <typename TIterator,
            typename TValue,
            typename TBinaryPredicate,
            typename TBinaryEquality>
  ETL_NODISCARD
  ETL_CONSTEXPR14
  TIterator binary_find(TIterator        begin,
                        TIterator        end,
                        const TValue&    value,
                        TBinaryPredicate predicate,
                        TBinaryEquality  equality)
  {
    TIterator it = etl::lower_bound(begin, end, value, predicate);
 
    if ((it == end) || !equality(*it, value))
    {
      it = end;
    }
 
    return it;
  }
 
  //***************************************************************************
  //***************************************************************************
  template <typename TIterator,
            typename TUnaryFunction,
            typename TUnaryPredicate>
  ETL_CONSTEXPR14
  TUnaryFunction for_each_if(TIterator       begin,
                             const TIterator end,
                             TUnaryFunction  function,
                             TUnaryPredicate predicate)
  {
    while (begin != end)
    {
      if (predicate(*begin))
      {
        function(*begin);
      }
 
      ++begin;
    }
 
    return function;
  }
 
  //***************************************************************************
  //***************************************************************************
  template <typename TIterator,
            typename TSize,
            typename TUnaryFunction>
  ETL_CONSTEXPR14
  TIterator for_each_n(TIterator       begin,
                       TSize           n,
                       TUnaryFunction  function)
  {
    while (n-- > 0)
    {
      function(*begin);
      ++begin;
    }
 
    return begin;
  }
 
  //***************************************************************************
  //***************************************************************************
  template <typename TIterator,
            typename TSize,
            typename TUnaryFunction,
            typename TUnaryPredicate>
  ETL_CONSTEXPR14
  TIterator for_each_n_if(TIterator       begin,
                          TSize           n,
                          TUnaryFunction  function,
                          TUnaryPredicate predicate)
  {
    while (n-- > 0)
    {
      if (predicate(*begin))
      {
        function(*begin);
      }
 
      ++begin;
    }
 
    return begin;
  }
 
  //***************************************************************************
  //***************************************************************************
  template <typename TInputIterator, typename TOutputIterator, typename TUnaryFunction>
  ETL_CONSTEXPR14
  TOutputIterator transform_s(TInputIterator  i_begin,
                              TInputIterator  i_end,
                              TOutputIterator o_begin,
                              TOutputIterator o_end,
                              TUnaryFunction  function)
  {
    while ((i_begin != i_end) && (o_begin != o_end))
    {
      *o_begin = function(*i_begin);
      ++i_begin;
      ++o_begin;
    }
 
    return o_begin;
  }
 
  //***************************************************************************
  //***************************************************************************
  template <typename TInputIterator,
            typename TSize,
            typename TOutputIterator,
            typename TUnaryFunction>
  ETL_CONSTEXPR14
  void transform_n(TInputIterator  i_begin,
                   TSize           n,
                   TOutputIterator o_begin,
                   TUnaryFunction  function)
  {
    TInputIterator i_end(i_begin);
    etl::advance(i_end, n);
 
    etl::transform(i_begin, i_end, o_begin, function);
  }
 
  //***************************************************************************
  //***************************************************************************
  template <typename TInputIterator1,
            typename TInputIterator2,
            typename TSize,
            typename TOutputIterator,
            typename TBinaryFunction>
  ETL_CONSTEXPR14
  void transform_n(TInputIterator1 i_begin1,
                   TInputIterator2 i_begin2,
                   TSize           n,
                   TOutputIterator o_begin,
                   TBinaryFunction function)
  {
    TInputIterator1 i_end1(i_begin1);
    etl::advance(i_end1, n);
 
    etl::transform(i_begin1, i_end1, i_begin2, o_begin, function);
  }
 
  //***************************************************************************
  //***************************************************************************
  template <typename TInputIterator,
            typename TOutputIterator,
            typename TUnaryFunction,
            typename TUnaryPredicate>
  ETL_CONSTEXPR14
  TOutputIterator transform_if(TInputIterator       i_begin,
                               const TInputIterator i_end,
                               TOutputIterator      o_begin,
                               TUnaryFunction       function,
                               TUnaryPredicate      predicate)
  {
    while (i_begin != i_end)
    {
      if (predicate(*i_begin))
      {
        *o_begin = function(*i_begin);
        ++o_begin;
      }
 
      ++i_begin;
    }
 
    return o_begin;
  }
 
  //***************************************************************************
  //***************************************************************************
  template <typename TInputIterator1,
            typename TInputIterator2,
            typename TOutputIterator,
            typename TBinaryFunction,
            typename TBinaryPredicate>
  ETL_CONSTEXPR14
  TOutputIterator transform_if(TInputIterator1       i_begin1,
                               const TInputIterator1 i_end1,
                               TInputIterator2       i_begin2,
                               TOutputIterator       o_begin,
                               TBinaryFunction       function,
                               TBinaryPredicate      predicate)
  {
    while (i_begin1 != i_end1)
    {
      if (predicate(*i_begin1, *i_begin2))
      {
        *o_begin = function(*i_begin1, *i_begin2);
        ++o_begin;
      }
 
      ++i_begin1;
      ++i_begin2;
    }
 
    return o_begin;
  }
 
  //***************************************************************************
  //***************************************************************************
  template <typename TInputIterator,
            typename TSize,
            typename TOutputIterator,
            typename TUnaryFunction,
            typename TUnaryPredicate>
  ETL_CONSTEXPR14
  TOutputIterator transform_n_if(TInputIterator  i_begin,
                                 TSize           n,
                                 TOutputIterator o_begin,
                                 TUnaryFunction  function,
                                 TUnaryPredicate predicate)
  {
    while (n-- > 0)
    {
      if (predicate(*i_begin))
      {
        *o_begin = function(*i_begin);
        ++o_begin;
      }
 
      ++i_begin;
    }
 
    return o_begin;
  }
 
  //***************************************************************************
  //***************************************************************************
  template <typename TInputIterator1,
            typename TInputIterator2,
            typename TSize,
            typename TOutputIterator,
            typename TBinaryFunction,
            typename TBinaryPredicate>
  ETL_CONSTEXPR14
  TOutputIterator transform_n_if(TInputIterator1  i_begin1,
                                 TInputIterator2  i_begin2,
                                 TSize            n,
                                 TOutputIterator  o_begin,
                                 TBinaryFunction  function,
                                 TBinaryPredicate predicate)
  {
    while (n-- > 0)
    {
      if (predicate(*i_begin1, *i_begin2))
      {
        *o_begin++ = function(*i_begin1, *i_begin2);
      }
 
      ++i_begin1;
      ++i_begin2;
    }
 
    return o_begin;
  }
 
  //***************************************************************************
  //***************************************************************************
  template <typename TSource, typename TDestinationTrue, typename TDestinationFalse,
            typename TUnaryFunctionTrue, typename TUnaryFunctionFalse,
            typename TUnaryPredicate>
  ETL_CONSTEXPR14
  ETL_OR_STD::pair<TDestinationTrue, TDestinationFalse> partition_transform(TSource             begin,
                                                                            TSource             end,
                                                                            TDestinationTrue    destination_true,
                                                                            TDestinationFalse   destination_false,
                                                                            TUnaryFunctionTrue  function_true,
                                                                            TUnaryFunctionFalse function_false,
                                                                            TUnaryPredicate     predicate)
  {
    while (begin != end)
    {
      if (predicate(*begin))
      {
        *destination_true = function_true(*begin);
        ++destination_true;
      }
      else
      {
        *destination_false = function_false(*begin);
        ++destination_false;
      }
 
      ++begin;
    }
 
    return ETL_OR_STD::pair<TDestinationTrue, TDestinationFalse>(destination_true, destination_false);
  }
 
  //***************************************************************************
  //***************************************************************************
  template <typename TSource1,
            typename TSource2,
            typename TDestinationTrue,
            typename TDestinationFalse,
            typename TBinaryFunctionTrue,
            typename TBinaryFunctionFalse,
            typename TBinaryPredicate>
  ETL_CONSTEXPR14
  ETL_OR_STD::pair<TDestinationTrue, TDestinationFalse> partition_transform(TSource1             begin1,
                                                                            TSource1             end1,
                                                                            TSource2             begin2,
                                                                            TDestinationTrue     destination_true,
                                                                            TDestinationFalse    destination_false,
                                                                            TBinaryFunctionTrue  function_true,
                                                                            TBinaryFunctionFalse function_false,
                                                                            TBinaryPredicate     predicate)
  {
    while (begin1 != end1)
    {
      if (predicate(*begin1, *begin2))
      {
        *destination_true = function_true(*begin1, *begin2);
        ++destination_true;
      }
      else
      {
        *destination_false = function_false(*begin1, *begin2);
        ++destination_false;
      }
 
      ++begin1;
      ++begin2;
    }
 
    return ETL_OR_STD::pair<TDestinationTrue, TDestinationFalse>(destination_true, destination_false);
  }
 
  //***************************************************************************
  //***************************************************************************
  template <typename TIterator, typename TCompare>
#if ETL_USING_STD_NAMESPACE
  ETL_CONSTEXPR20
#else
  ETL_CONSTEXPR14
#endif
  void shell_sort(TIterator first, TIterator last, TCompare compare)
  {
    if (first == last)
    {
      return;
    }
 
    typedef typename etl::iterator_traits<TIterator>::difference_type difference_t;
 
    difference_t n = etl::distance(first, last);
 
    for (difference_t i = n / 2; i > 0; i /= 2)
    {
      for (difference_t j = i; j < n; ++j)
      {
        for (difference_t k = j - i; k >= 0; k -= i)
        {
          TIterator itr1 = first;
          TIterator itr2 = first;
 
          etl::advance(itr1, k);
          etl::advance(itr2, k + i);
 
          if (compare(*itr2, *itr1))
          {
            etl::iter_swap(itr1, itr2);
          }
        }
      }
    }
  }
 
  //***************************************************************************
  //***************************************************************************
  template <typename TIterator>
#if ETL_USING_STD_NAMESPACE
  ETL_CONSTEXPR20
#else
  ETL_CONSTEXPR14
#endif
  void shell_sort(TIterator first, TIterator last)
  {
    etl::shell_sort(first, last, etl::less<typename etl::iterator_traits<TIterator>::value_type>());
  }
 
  //***************************************************************************
  //***************************************************************************
  template <typename TIterator, typename TCompare>
  ETL_CONSTEXPR14
  void insertion_sort(TIterator first, TIterator last, TCompare compare)
  {
    for (TIterator itr = first; itr != last; ++itr)
    {
      etl::rotate(etl::upper_bound(first, itr, *itr, compare), itr, etl::next(itr));
    }
  }
 
  //***************************************************************************
  //***************************************************************************
  template <typename TIterator>
  ETL_CONSTEXPR14
  void insertion_sort(TIterator first, TIterator last)
  {
    etl::insertion_sort(first, last, etl::less<typename etl::iterator_traits<TIterator>::value_type>());
  }
 
  //***************************************************************************
  namespace private_algorithm
  {
    template <typename TIterator>
    ETL_CONSTEXPR14
    typename etl::enable_if<etl::is_forward_iterator<TIterator>::value, TIterator>::type
      get_before_last(TIterator first_, TIterator last_)
    {
      TIterator last      = first_;
      TIterator lastplus1 = first_;
      ++lastplus1;
 
      while (lastplus1 != last_)
      {
        ++last;
        ++lastplus1;
      }
 
      return last;
    }
 
    template <typename TIterator>
    ETL_CONSTEXPR14
    typename etl::enable_if<etl::is_bidirectional_iterator<TIterator>::value, TIterator>::type
      get_before_last(TIterator /*first_*/, TIterator last_)
    {
      TIterator last = last_;
      --last;
 
      return last;
    }
 
    template <typename TIterator>
    ETL_CONSTEXPR14
    typename etl::enable_if<etl::is_random_access_iterator<TIterator>::value, TIterator>::type
      get_before_last(TIterator /*first_*/, TIterator last_)
    {
      return last_ - 1;
    }
  }
 
  //***************************************************************************
  //***************************************************************************
  template <typename TIterator, typename TCompare>
  ETL_CONSTEXPR20
  void selection_sort(TIterator first, TIterator last, TCompare compare)
  {
    TIterator min;
    const TIterator ilast = private_algorithm::get_before_last(first, last);
    const TIterator jlast = last;
 
    for (TIterator i = first; i != ilast; ++i)
    {
      min = i;
      
      TIterator j = i;
      ++j;
 
      for (; j != jlast; ++j)
      {
        if (compare(*j, *min))
        {
          min = j;
        }
      }
 
      using ETL_OR_STD::swap; // Allow ADL
      swap(*i, *min);
    }
  }
 
  //***************************************************************************
  //***************************************************************************
  template <typename TIterator>
  ETL_CONSTEXPR20
  void selection_sort(TIterator first, TIterator last)
  {
    selection_sort(first, last, etl::less<typename etl::iterator_traits<TIterator>::value_type>());
  }
 
  //***************************************************************************
  //***************************************************************************
  template <typename TIterator, typename TCompare>
  ETL_CONSTEXPR14
  void heap_sort(TIterator first, TIterator last, TCompare compare)
  {
    if (!etl::is_heap(first, last, compare))
    {
      etl::make_heap(first, last, compare);
    }
 
    etl::sort_heap(first, last, compare);
  }
 
  //***************************************************************************
  //***************************************************************************
  template <typename TIterator>
  ETL_CONSTEXPR14
  void heap_sort(TIterator first, TIterator last)
  {
    if (!etl::is_heap(first, last))
    {
      etl::make_heap(first, last);
    }
 
    etl::sort_heap(first, last);
  }
 
  //***************************************************************************
  //***************************************************************************
#if ETL_USING_CPP11
  template <typename T>
  ETL_NODISCARD
  constexpr const T& multimax(const T& a, const T& b)
  {
    return a < b ? b : a;
  }
 
  template <typename T, typename... Tx>
  ETL_NODISCARD
  constexpr const T& multimax(const T& t, const Tx&... tx)
  {
    return multimax(t, multimax(tx...));
  }
#endif
 
  //***************************************************************************
  //***************************************************************************
#if ETL_USING_CPP11
  template <typename TCompare, typename T>
  ETL_NODISCARD
  constexpr const T& multimax_compare(TCompare compare, const T& a, const T& b)
  {
    return compare(a, b) ? b : a;
  }
 
  template <typename TCompare, typename T, typename... Tx>
  ETL_NODISCARD
  constexpr const T& multimax_compare(TCompare compare, const T& t, const Tx&... tx)
  {
    return multimax_compare(compare, t, multimax_compare(compare, tx...));
  }
#endif
 
  //***************************************************************************
  //***************************************************************************
#if ETL_USING_CPP11
  template <typename T>
  ETL_NODISCARD
  constexpr const T& multimin(const T& a, const T& b)
  {
    return a < b ? a : b;
  }
 
  template <typename T, typename... Tx>
  ETL_NODISCARD
  constexpr const T& multimin(const T& t, const Tx&... tx)
  {
    return multimin(t, multimin(tx...));
  }
#endif
 
  //***************************************************************************
  //***************************************************************************
#if ETL_USING_CPP11
  template <typename TCompare, typename T>
  ETL_NODISCARD
  constexpr const T& multimin_compare(TCompare compare, const T& a, const T& b)
  {
    return compare(a, b) ? a : b;
  }
 
  template <typename TCompare, typename T, typename... Tx>
  ETL_NODISCARD
  constexpr const T& multimin_compare(TCompare compare, const T& t, const Tx&... tx)
  {
    return multimin_compare(compare, t, multimin_compare(compare, tx...));
  }
#endif
 
  //***************************************************************************
  //***************************************************************************
#if ETL_USING_CPP11
  template <typename TIterator>
  ETL_NODISCARD
  constexpr const TIterator& multimax_iter(const TIterator& a, const TIterator& b)
  {
    return *a < *b ? b : a;
  }
 
  template <typename TIterator, typename... TIteratorx>
  ETL_NODISCARD
  constexpr const TIterator& multimax_iter(const TIterator& t, const TIteratorx&... tx)
  {
    return multimax_iter(t, multimax_iter(tx...));
  }
#endif
 
  //***************************************************************************
  //***************************************************************************
#if ETL_USING_CPP11
  template <typename TCompare, typename TIterator>
  ETL_NODISCARD
  constexpr const TIterator& multimax_iter_compare(TCompare compare, const TIterator& a, const TIterator& b)
  {
    return compare(*a, *b) ? b : a;
  }
 
  template <typename TCompare, typename TIterator, typename... TIteratorx>
  ETL_NODISCARD
  constexpr const TIterator& multimax_iter_compare(TCompare compare, const TIterator& t, const TIteratorx&... tx)
  {
    return multimax_iter_compare(compare, t, multimax_iter_compare(compare, tx...));
  }
#endif
 
  //***************************************************************************
  //***************************************************************************
#if ETL_USING_CPP11
  template <typename TIterator>
  ETL_NODISCARD
  constexpr const TIterator& multimin_iter(const TIterator& a, const TIterator& b)
  {
    return *a < *b ? a : b;
  }
 
  template <typename TIterator, typename... Tx>
  ETL_NODISCARD
  constexpr const TIterator& multimin_iter(const TIterator& t, const Tx&... tx)
  {
    return multimin_iter(t, multimin_iter(tx...));
  }
#endif
 
  //***************************************************************************
  //***************************************************************************
#if ETL_USING_CPP11
  template <typename TCompare, typename TIterator>
  ETL_NODISCARD
  constexpr const TIterator& multimin_iter_compare(TCompare compare, const TIterator& a, const TIterator& b)
  {
    return compare(*a, *b) ? a : b;
  }
 
  template <typename TCompare, typename TIterator, typename... Tx>
  ETL_NODISCARD
  constexpr const TIterator& multimin_iter_compare(TCompare compare, const TIterator& t, const Tx&... tx)
  {
    return multimin_iter_compare(compare, t, multimin_iter_compare(compare, tx...));
  }
#endif
 
  //***************************************************************************
  //***************************************************************************
  template <typename TIterator, typename TPredicate>
  ETL_CONSTEXPR14 
  typename etl::enable_if<etl::is_forward_iterator<TIterator>::value, TIterator>::type
    partition(TIterator first, TIterator last, TPredicate predicate)
  {
    first = etl::find_if_not(first, last, predicate);
 
    if (first == last)
    {
      return first;
    }
 
    for (TIterator i = etl::next(first); i != last; ++i)
    {
      if (predicate(*i))
      {
        using ETL_OR_STD::swap;
        swap(*i, *first);
        ++first;
      }
    }
 
    return first;
  }
 
  //***************************************************************************
  //***************************************************************************
  template <typename TIterator, typename TPredicate>
  ETL_CONSTEXPR14
  typename etl::enable_if<etl::is_bidirectional_iterator_concept<TIterator>::value, TIterator>::type
    partition(TIterator first, TIterator last, TPredicate predicate) 
  {
    while (first != last)
    {
      first = etl::find_if_not(first, last, predicate);
 
      if (first == last)
      {
        break;
      }
 
      last = etl::find_if(etl::reverse_iterator<TIterator>(last),
                          etl::reverse_iterator<TIterator>(first),
                          predicate).base();
 
      if (first == last)
      {
        break;
      }
 
      --last;
      using ETL_OR_STD::swap;
      swap(*first, *last);
      ++first;
    }
 
    return first;
  }
 
  //*********************************************************
  namespace private_algorithm
  {
    using ETL_OR_STD::swap;
 
    template <typename TIterator, typename TCompare>
#if (ETL_USING_CPP20 && ETL_USING_STL) || (ETL_USING_CPP14 && ETL_NOT_USING_STL && !defined(ETL_IN_UNIT_TEST))
    constexpr
#endif
    TIterator nth_partition(TIterator first, TIterator last, TCompare compare)
    {
      typedef typename etl::iterator_traits<TIterator>::value_type value_type;
 
      TIterator  pivot = last; // Maybe find a better pivot choice?
      value_type pivot_value = *pivot;
 
      // Swap the pivot with the last, if necessary.
      if (pivot != last)
      {
        swap(*pivot, *last);
      }
 
      TIterator i = first;
 
      for (TIterator j = first; j < last; ++j)
      {
        if (!compare(pivot_value, *j)) // Hack to get '*j <= pivot_value' in terms of 'pivot_value < *j'
        {
          swap(*i, *j);
          ++i;
        }
      }
 
      swap(*i, *last);
 
      return i;
    }
  }
 
  //*********************************************************
  //*********************************************************
#if ETL_USING_CPP11
  template <typename TIterator, typename TCompare = etl::less<typename etl::iterator_traits<TIterator>::value_type>>
#if (ETL_USING_CPP20 && ETL_USING_STL) || (ETL_USING_CPP14 && ETL_NOT_USING_STL && !defined(ETL_IN_UNIT_TEST))
  constexpr
#endif
  typename etl::enable_if<etl::is_random_access_iterator_concept<TIterator>::value, void>::type
    nth_element(TIterator first, TIterator nth, TIterator last, TCompare compare = TCompare())
  {
    if (first == last)
    {
      return;
    }
 
    // 'last' must point to the actual last value.
    --last;
 
    while (first <= last)
    {
      TIterator p = private_algorithm::nth_partition(first, last, compare);
 
      if (p == nth)
      {
        return;
      }
      else if (p > nth)
      {
        last = p - 1;
      }
      else
      {
        first = p + 1;
      }
    }
  }
 
#else
 
  //*********************************************************
  template <typename TIterator, typename TCompare>
  typename etl::enable_if<etl::is_random_access_iterator_concept<TIterator>::value, void>::type
    nth_element(TIterator first, TIterator nth, TIterator last, TCompare compare)
  {
    if (first == last)
    {
      return;
    }
 
    // 'last' must point to the actual last value.
    --last;
 
    while (first <= last)
    {
      TIterator p = private_algorithm::nth_partition(first, last, compare);
 
      if (p == nth)
      {
        return;
      }
      else if (p > nth)
      {
        last = p - 1;
      }
      else
      {
        first = p + 1;
      }
    }
  }
 
  //*********************************************************
  template <typename TIterator>
  typename etl::enable_if<etl::is_random_access_iterator_concept<TIterator>::value, void>::type
    nth_element(TIterator first, TIterator nth, TIterator last)
  {
    typedef etl::less<typename etl::iterator_traits<TIterator>::value_type> compare_t;
 
    nth_element(first, last, compare_t());
  }
#endif
}
 
#include "private/minmax_pop.h"
 
#endif