| 123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167168169170171172173174175176177178179180181182183184185186187188189190191192193194195196197198199200201202203204205206207208209210211212213214215216217218219220221222223224225226227228229230231232233234235236237238239240241242243244245246247248249250251252253254255256257258259260261262263264265266267268269270271272273274275276277278279280281282283284285286287288289290291292293294295296297298299300301302303304305306307308309310311312313314315316317318319320321322323324325326327328329330331332333334335336337338339340341342343344345346347348349350351352353354355356357358359360361362363364365366367368369370371372373374375376377378379380381382383384385386387388389390391392393394395396397398399400401402403404405406407408409410411412413414415416417418419420421422423424425426427428429430431432433434435436437438439440441442443444445446447448449450451452453454455456457458459460461462463464465466467468469470471472473474475476477478479480481482483484485486487488489490491492493494495496497498499500501502503504505506507508509510511512513514515516517518519520521522523524525526527528529530531532533534535536537538539540541542543544545546547548549550551552553554555556557558559560561562563564565566567568569570571572573574575576577578579580581582583584585586587588589590591592593594595596597598599600601602603604605606607608609610611612613614615616617618619620621622623624625626627628629630631632633634635636637638639640641642643644645646647648649650651652653654655656657658659660661662663664665666667668669670671672673674675676677678679680681682683684685686687688689690691692693694695696697698699700701702703 | // <numeric> -*- C++ -*-// Copyright (C) 2001-2019 Free Software Foundation, Inc.//// This file is part of the GNU ISO C++ Library.  This library is free// software; you can redistribute it and/or modify it under the// terms of the GNU General Public License as published by the// Free Software Foundation; either version 3, or (at your option)// any later version.// This library is distributed in the hope that it will be useful,// but WITHOUT ANY WARRANTY; without even the implied warranty of// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the// GNU General Public License for more details.// Under Section 7 of GPL version 3, you are granted additional// permissions described in the GCC Runtime Library Exception, version// 3.1, as published by the Free Software Foundation.// You should have received a copy of the GNU General Public License and// a copy of the GCC Runtime Library Exception along with this program;// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see// <http://www.gnu.org/licenses/>./* * * Copyright (c) 1994 * Hewlett-Packard Company * * Permission to use, copy, modify, distribute and sell this software * and its documentation for any purpose is hereby granted without fee, * provided that the above copyright notice appear in all copies and * that both that copyright notice and this permission notice appear * in supporting documentation.  Hewlett-Packard Company makes no * representations about the suitability of this software for any * purpose.  It is provided "as is" without express or implied warranty. * * * Copyright (c) 1996,1997 * Silicon Graphics Computer Systems, Inc. * * Permission to use, copy, modify, distribute and sell this software * and its documentation for any purpose is hereby granted without fee, * provided that the above copyright notice appear in all copies and * that both that copyright notice and this permission notice appear * in supporting documentation.  Silicon Graphics makes no * representations about the suitability of this software for any * purpose.  It is provided "as is" without express or implied warranty. *//** @file include/numeric *  This is a Standard C++ Library header. */#ifndef _GLIBCXX_NUMERIC#define _GLIBCXX_NUMERIC 1#pragma GCC system_header#include <bits/c++config.h>#include <bits/stl_iterator_base_types.h>#include <bits/stl_numeric.h>#ifdef _GLIBCXX_PARALLEL# include <parallel/numeric>#endif/** * @defgroup numerics Numerics * * Components for performing numeric operations. Includes support for * complex number types, random number generation, numeric (n-at-a-time) * arrays, generalized numeric algorithms, and mathematical special functions. */#if __cplusplus >= 201402L#include <type_traits>namespace std _GLIBCXX_VISIBILITY(default){_GLIBCXX_BEGIN_NAMESPACE_VERSIONnamespace __detail{  // std::abs is not constexpr and doesn't support unsigned integers.  template<typename _Tp>    constexpr    enable_if_t<__and_<is_integral<_Tp>, is_signed<_Tp>>::value, _Tp>    __abs_integral(_Tp __val)    { return __val < 0 ? -__val : __val; }  template<typename _Tp>    constexpr    enable_if_t<__and_<is_integral<_Tp>, is_unsigned<_Tp>>::value, _Tp>    __abs_integral(_Tp __val)    { return __val; }  void __abs_integral(bool) = delete;  template<typename _Mn, typename _Nn>    constexpr common_type_t<_Mn, _Nn>    __gcd(_Mn __m, _Nn __n)    {      return __m == 0 ? __detail::__abs_integral(__n)	: __n == 0 ? __detail::__abs_integral(__m)	: __detail::__gcd(__n, __m % __n);    }  /// Least common multiple  template<typename _Mn, typename _Nn>    constexpr common_type_t<_Mn, _Nn>    __lcm(_Mn __m, _Nn __n)    {      return (__m != 0 && __n != 0)	? (__detail::__abs_integral(__m) / __detail::__gcd(__m, __n))	  * __detail::__abs_integral(__n)	: 0;    }} // namespace __detail#if __cplusplus >= 201703L#define __cpp_lib_gcd_lcm 201606// These were used in drafts of SD-6:#define __cpp_lib_gcd 201606#define __cpp_lib_lcm 201606  /// Greatest common divisor  template<typename _Mn, typename _Nn>    constexpr common_type_t<_Mn, _Nn>    gcd(_Mn __m, _Nn __n)    {      static_assert(is_integral_v<_Mn>, "gcd arguments are integers");      static_assert(is_integral_v<_Nn>, "gcd arguments are integers");      static_assert(!is_same_v<remove_cv_t<_Mn>, bool>,		    "gcd arguments are not bools");      static_assert(!is_same_v<remove_cv_t<_Nn>, bool>,		    "gcd arguments are not bools");      return __detail::__gcd(__m, __n);    }  /// Least common multiple  template<typename _Mn, typename _Nn>    constexpr common_type_t<_Mn, _Nn>    lcm(_Mn __m, _Nn __n)    {      static_assert(is_integral_v<_Mn>, "lcm arguments are integers");      static_assert(is_integral_v<_Nn>, "lcm arguments are integers");      static_assert(!is_same_v<remove_cv_t<_Mn>, bool>,		    "lcm arguments are not bools");      static_assert(!is_same_v<remove_cv_t<_Nn>, bool>,		    "lcm arguments are not bools");      return __detail::__lcm(__m, __n);    }#endif // C++17_GLIBCXX_END_NAMESPACE_VERSION} // namespace std#endif // C++14#if __cplusplus > 201703L#include <limits>namespace std _GLIBCXX_VISIBILITY(default){_GLIBCXX_BEGIN_NAMESPACE_VERSION  // midpoint# define __cpp_lib_interpolate 201902L  template<typename _Tp>    constexpr    enable_if_t<__and_v<is_arithmetic<_Tp>, is_same<remove_cv_t<_Tp>, _Tp>,			__not_<is_same<_Tp, bool>>>,		_Tp>    midpoint(_Tp __a, _Tp __b) noexcept    {      if constexpr (is_integral_v<_Tp>)	{	  using _Up = make_unsigned_t<_Tp>;	  int __k = 1;	  _Up __m = __a;	  _Up __M = __b;	  if (__a > __b)	    {	      __k = -1;	      __m = __b;	      __M = __a;	    }	  return __a + __k * _Tp(_Up(__M - __m) / 2);	}      else // is_floating	{	  constexpr _Tp __lo = numeric_limits<_Tp>::min() * 2;	  constexpr _Tp __hi = numeric_limits<_Tp>::max() / 2;	  const _Tp __abs_a = __a < 0 ? -__a : __a;	  const _Tp __abs_b = __b < 0 ? -__b : __b;	  if (__abs_a <= __hi && __abs_b <= __hi) [[likely]]	    return (__a + __b) / 2; // always correctly rounded	  if (__abs_a < __lo) // not safe to halve __a	    return __a + __b/2;	  if (__abs_b < __lo) // not safe to halve __b	    return __a/2 + __b;	  return __a/2 + __b/2;	    // otherwise correctly rounded	}    }  template<typename _Tp>    constexpr    enable_if_t<__and_v<is_object<_Tp>, bool_constant<sizeof(_Tp) != 0>>, _Tp*>    midpoint(_Tp* __a, _Tp* __b) noexcept    {      return __a  + (__b - __a) / 2;    }_GLIBCXX_END_NAMESPACE_VERSION} // namespace std#endif // C++20#if __cplusplus > 201402L#include <bits/stl_function.h>namespace std _GLIBCXX_VISIBILITY(default){_GLIBCXX_BEGIN_NAMESPACE_VERSION  /// @addtogroup numeric_ops  /// @{  /// @cond undocumented  template<typename _It, typename _Traits = iterator_traits<_It>,	   typename _Cat = typename _Traits::iterator_category>    using __is_random_access_iter      = is_base_of<random_access_iterator_tag, _Cat>;  /// @endcond  /**   *  @brief  Calculate reduction of values in a range.   *   *  @param  __first  Start of range.   *  @param  __last  End of range.   *  @param  __init  Starting value to add other values to.   *  @param  __binary_op A binary function object.   *  @return  The final sum.   *   *  Reduce the values in the range `[first,last)` using a binary operation.   *  The initial value is `init`.  The values are not necessarily processed   *  in order.   *   *  This algorithm is similar to `std::accumulate` but is not required to   *  perform the operations in order from first to last. For operations   *  that are commutative and associative the result will be the same as   *  for `std::accumulate`, but for other operations (such as floating point   *  arithmetic) the result can be different.   */  template<typename _InputIterator, typename _Tp, typename _BinaryOperation>    _Tp    reduce(_InputIterator __first, _InputIterator __last, _Tp __init,	   _BinaryOperation __binary_op)    {      using value_type = typename iterator_traits<_InputIterator>::value_type;      static_assert(is_invocable_r_v<_Tp, _BinaryOperation&, _Tp&, _Tp&>);      static_assert(is_convertible_v<value_type, _Tp>);      if constexpr (__is_random_access_iter<_InputIterator>::value)	{	  while ((__last - __first) >= 4)	    {	      _Tp __v1 = __binary_op(__first[0], __first[1]);	      _Tp __v2 = __binary_op(__first[2], __first[3]);	      _Tp __v3 = __binary_op(__v1, __v2);	      __init = __binary_op(__init, __v3);	      __first += 4;	    }	}      for (; __first != __last; ++__first)	__init = __binary_op(__init, *__first);      return __init;    } /**   *  @brief  Calculate reduction of values in a range.   *   *  @param  __first  Start of range.   *  @param  __last  End of range.   *  @param  __init  Starting value to add other values to.   *  @return  The final sum.   *   *  Reduce the values in the range `[first,last)` using addition.   *  Equivalent to calling `std::reduce(first, last, init, std::plus<>())`.   */  template<typename _InputIterator, typename _Tp>    inline _Tp    reduce(_InputIterator __first, _InputIterator __last, _Tp __init)    { return std::reduce(__first, __last, std::move(__init), plus<>()); }  /**   *  @brief  Calculate reduction of values in a range.   *   *  @param  __first  Start of range.   *  @param  __last  End of range.   *  @return  The final sum.   *   *  Reduce the values in the range `[first,last)` using addition, with   *  an initial value of `T{}`, where `T` is the iterator's value type.   *  Equivalent to calling `std::reduce(first, last, T{}, std::plus<>())`.   */  template<typename _InputIterator>    inline typename iterator_traits<_InputIterator>::value_type    reduce(_InputIterator __first, _InputIterator __last)    {      using value_type = typename iterator_traits<_InputIterator>::value_type;      return std::reduce(__first, __last, value_type{}, plus<>());    }  /**   *  @brief  Combine elements from two ranges and reduce   *   *  @param  __first1  Start of first range.   *  @param  __last1  End of first range.   *  @param  __first2  Start of second range.   *  @param  __init  Starting value to add other values to.   *  @param  __binary_op1 The function used to perform reduction.   *  @param  __binary_op2 The function used to combine values from the ranges.   *  @return  The final sum.   *   *  Call `binary_op2(first1[n],first2[n])` for each `n` in `[0,last1-first1)`   *  and then use `binary_op1` to reduce the values returned by `binary_op2`   *  to a single value of type `T`.   *   *  The range beginning at `first2` must contain at least `last1-first1`   *  elements.   */  template<typename _InputIterator1, typename _InputIterator2, typename _Tp,	   typename _BinaryOperation1, typename _BinaryOperation2>    _Tp    transform_reduce(_InputIterator1 __first1, _InputIterator1 __last1,		     _InputIterator2 __first2, _Tp __init,		     _BinaryOperation1 __binary_op1,		     _BinaryOperation2 __binary_op2)    {      if constexpr (__and_v<__is_random_access_iter<_InputIterator1>,			    __is_random_access_iter<_InputIterator2>>)	{	  while ((__last1 - __first1) >= 4)	    {	      _Tp __v1 = __binary_op1(__binary_op2(__first1[0], __first2[0]),				      __binary_op2(__first1[1], __first2[1]));	      _Tp __v2 = __binary_op1(__binary_op2(__first1[2], __first2[2]),				      __binary_op2(__first1[3], __first2[3]));	      _Tp __v3 = __binary_op1(__v1, __v2);	      __init = __binary_op1(__init, __v3);	      __first1 += 4;	      __first2 += 4;	    }	}      for (; __first1 != __last1; ++__first1, (void) ++__first2)	__init = __binary_op1(__init, __binary_op2(*__first1, *__first2));      return __init;    }  /**   *  @brief  Combine elements from two ranges and reduce   *   *  @param  __first1  Start of first range.   *  @param  __last1  End of first range.   *  @param  __first2  Start of second range.   *  @param  __init  Starting value to add other values to.   *  @return  The final sum.   *   *  Call `first1[n]*first2[n]` for each `n` in `[0,last1-first1)` and then   *  use addition to sum those products to a single value of type `T`.   *   *  The range beginning at `first2` must contain at least `last1-first1`   *  elements.   */  template<typename _InputIterator1, typename _InputIterator2, typename _Tp>    inline _Tp    transform_reduce(_InputIterator1 __first1, _InputIterator1 __last1,		     _InputIterator2 __first2, _Tp __init)    {      return std::transform_reduce(__first1, __last1, __first2,				   std::move(__init),				   plus<>(), multiplies<>());    }  /**   *  @brief  Transform the elements of a range and reduce   *   *  @param  __first  Start of range.   *  @param  __last  End of range.   *  @param  __init  Starting value to add other values to.   *  @param  __binary_op The function used to perform reduction.   *  @param  __unary_op The function used to transform values from the range.   *  @return  The final sum.   *   *  Call `unary_op(first[n])` for each `n` in `[0,last-first)` and then   *  use `binary_op` to reduce the values returned by `unary_op`   *  to a single value of type `T`.   */  template<typename _InputIterator, typename _Tp,	   typename _BinaryOperation, typename _UnaryOperation>    _Tp    transform_reduce(_InputIterator __first, _InputIterator __last, _Tp __init,		     _BinaryOperation __binary_op, _UnaryOperation __unary_op)    {      if constexpr (__is_random_access_iter<_InputIterator>::value)	{	  while ((__last - __first) >= 4)	    {	      _Tp __v1 = __binary_op(__unary_op(__first[0]),				     __unary_op(__first[1]));	      _Tp __v2 = __binary_op(__unary_op(__first[2]),				     __unary_op(__first[3]));	      _Tp __v3 = __binary_op(__v1, __v2);	      __init = __binary_op(__init, __v3);	      __first += 4;	    }	}      for (; __first != __last; ++__first)	__init = __binary_op(__init, __unary_op(*__first));      return __init;    }  /** @brief Output the cumulative sum of one range to a second range   *   *  @param __first  Start of input range.   *  @param __last   End of input range.   *  @param __result Start of output range.   *  @param __init   Initial value.   *  @param __binary_op Function to perform summation.   *  @return The end of the output range.   *   *  Write the cumulative sum (aka prefix sum, aka scan) of the input range   *  to the output range. Each element of the output range contains the   *  running total of all earlier elements (and the initial value),   *  using `binary_op` for summation.   *   *  This function generates an "exclusive" scan, meaning the Nth element   *  of the output range is the sum of the first N-1 input elements,   *  so the Nth input element is not included.   */  template<typename _InputIterator, typename _OutputIterator, typename _Tp,	   typename _BinaryOperation>    _OutputIterator    exclusive_scan(_InputIterator __first, _InputIterator __last,		   _OutputIterator __result, _Tp __init,		   _BinaryOperation __binary_op)    {      while (__first != __last)	{	  auto __v = __init;	  __init = __binary_op(__init, *__first);	  ++__first;	  *__result++ = std::move(__v);	}      return __result;    }  /** @brief Output the cumulative sum of one range to a second range   *   *  @param __first  Start of input range.   *  @param __last   End of input range.   *  @param __result Start of output range.   *  @param __init   Initial value.   *  @return The end of the output range.   *   *  Write the cumulative sum (aka prefix sum, aka scan) of the input range   *  to the output range. Each element of the output range contains the   *  running total of all earlier elements (and the initial value),   *  using `std::plus<>` for summation.   *   *  This function generates an "exclusive" scan, meaning the Nth element   *  of the output range is the sum of the first N-1 input elements,   *  so the Nth input element is not included.   */  template<typename _InputIterator, typename _OutputIterator, typename _Tp>    inline _OutputIterator    exclusive_scan(_InputIterator __first, _InputIterator __last,		   _OutputIterator __result, _Tp __init)    {      return std::exclusive_scan(__first, __last, __result, std::move(__init),				 plus<>());    }  /** @brief Output the cumulative sum of one range to a second range   *   *  @param __first  Start of input range.   *  @param __last   End of input range.   *  @param __result Start of output range.   *  @param __binary_op Function to perform summation.   *  @param __init   Initial value.   *  @return The end of the output range.   *   *  Write the cumulative sum (aka prefix sum, aka scan) of the input range   *  to the output range. Each element of the output range contains the   *  running total of all earlier elements (and the initial value),   *  using `binary_op` for summation.   *   *  This function generates an "inclusive" scan, meaning the Nth element   *  of the output range is the sum of the first N input elements,   *  so the Nth input element is included.   */  template<typename _InputIterator, typename _OutputIterator,	   typename _BinaryOperation, typename _Tp>    _OutputIterator    inclusive_scan(_InputIterator __first, _InputIterator __last,		   _OutputIterator __result, _BinaryOperation __binary_op,		   _Tp __init)    {      for (; __first != __last; ++__first)	*__result++ = __init = __binary_op(__init, *__first);      return __result;    }  /** @brief Output the cumulative sum of one range to a second range   *   *  @param __first  Start of input range.   *  @param __last   End of input range.   *  @param __result Start of output range.   *  @param __binary_op Function to perform summation.   *  @return The end of the output range.   *   *  Write the cumulative sum (aka prefix sum, aka scan) of the input range   *  to the output range. Each element of the output range contains the   *  running total of all earlier elements, using `binary_op` for summation.   *   *  This function generates an "inclusive" scan, meaning the Nth element   *  of the output range is the sum of the first N input elements,   *  so the Nth input element is included.   */  template<typename _InputIterator, typename _OutputIterator,	   typename _BinaryOperation>    _OutputIterator    inclusive_scan(_InputIterator __first, _InputIterator __last,		   _OutputIterator __result, _BinaryOperation __binary_op)    {      if (__first != __last)	{	  auto __init = *__first;	  *__result++ = __init;	  ++__first;	  if (__first != __last)	    __result = std::inclusive_scan(__first, __last, __result,					   __binary_op, std::move(__init));	}      return __result;    }  /** @brief Output the cumulative sum of one range to a second range   *   *  @param __first  Start of input range.   *  @param __last   End of input range.   *  @param __result Start of output range.   *  @return The end of the output range.   *   *  Write the cumulative sum (aka prefix sum, aka scan) of the input range   *  to the output range. Each element of the output range contains the   *  running total of all earlier elements, using `std::plus<>` for summation.   *   *  This function generates an "inclusive" scan, meaning the Nth element   *  of the output range is the sum of the first N input elements,   *  so the Nth input element is included.   */  template<typename _InputIterator, typename _OutputIterator>    inline _OutputIterator    inclusive_scan(_InputIterator __first, _InputIterator __last,		   _OutputIterator __result)    { return std::inclusive_scan(__first, __last, __result, plus<>()); }  /** @brief Output the cumulative sum of one range to a second range   *   *  @param __first  Start of input range.   *  @param __last   End of input range.   *  @param __result Start of output range.   *  @param __init   Initial value.   *  @param __binary_op Function to perform summation.   *  @param __unary_op Function to transform elements of the input range.   *  @return The end of the output range.   *   *  Write the cumulative sum (aka prefix sum, aka scan) of the input range   *  to the output range. Each element of the output range contains the   *  running total of all earlier elements (and the initial value),   *  using `__unary_op` to transform the input elements   *  and using `__binary_op` for summation.   *   *  This function generates an "exclusive" scan, meaning the Nth element   *  of the output range is the sum of the first N-1 input elements,   *  so the Nth input element is not included.   */  template<typename _InputIterator, typename _OutputIterator, typename _Tp,	   typename _BinaryOperation, typename _UnaryOperation>    _OutputIterator    transform_exclusive_scan(_InputIterator __first, _InputIterator __last,			     _OutputIterator __result, _Tp __init,			     _BinaryOperation __binary_op,			     _UnaryOperation __unary_op)    {      while (__first != __last)	{	  auto __v = __init;	  __init = __binary_op(__init, __unary_op(*__first));	  ++__first;	  *__result++ = std::move(__v);	}      return __result;    }  /** @brief Output the cumulative sum of one range to a second range   *   *  @param __first  Start of input range.   *  @param __last   End of input range.   *  @param __result Start of output range.   *  @param __binary_op Function to perform summation.   *  @param __unary_op Function to transform elements of the input range.   *  @param __init   Initial value.   *  @return The end of the output range.   *   *  Write the cumulative sum (aka prefix sum, aka scan) of the input range   *  to the output range. Each element of the output range contains the   *  running total of all earlier elements (and the initial value),   *  using `__unary_op` to transform the input elements   *  and using `__binary_op` for summation.   *   *  This function generates an "inclusive" scan, meaning the Nth element   *  of the output range is the sum of the first N input elements,   *  so the Nth input element is included.   */  template<typename _InputIterator, typename _OutputIterator,	   typename _BinaryOperation, typename _UnaryOperation, typename _Tp>    _OutputIterator    transform_inclusive_scan(_InputIterator __first, _InputIterator __last,			     _OutputIterator __result,			     _BinaryOperation __binary_op,			     _UnaryOperation __unary_op,			     _Tp __init)    {      for (; __first != __last; ++__first)	*__result++ = __init = __binary_op(__init, __unary_op(*__first));      return __result;    }  /** @brief Output the cumulative sum of one range to a second range   *   *  @param __first  Start of input range.   *  @param __last   End of input range.   *  @param __result Start of output range.   *  @param __binary_op Function to perform summation.   *  @param __unary_op Function to transform elements of the input range.   *  @return The end of the output range.   *   *  Write the cumulative sum (aka prefix sum, aka scan) of the input range   *  to the output range. Each element of the output range contains the   *  running total of all earlier elements,   *  using `__unary_op` to transform the input elements   *  and using `__binary_op` for summation.   *   *  This function generates an "inclusive" scan, meaning the Nth element   *  of the output range is the sum of the first N input elements,   *  so the Nth input element is included.   */  template<typename _InputIterator, typename _OutputIterator,	  typename _BinaryOperation, typename _UnaryOperation>    _OutputIterator    transform_inclusive_scan(_InputIterator __first, _InputIterator __last,			     _OutputIterator __result,			     _BinaryOperation __binary_op,			     _UnaryOperation __unary_op)    {      if (__first != __last)	{	  auto __init = __unary_op(*__first);	  *__result++ = __init;	  ++__first;	  if (__first != __last)	    __result = std::transform_inclusive_scan(__first, __last, __result,						     __binary_op, __unary_op,						     std::move(__init));	}      return __result;    }  // @} group numeric_ops_GLIBCXX_END_NAMESPACE_VERSION} // namespace std// Parallel STL algorithms# if __PSTL_EXECUTION_POLICIES_DEFINED// If <execution> has already been included, pull in implementations#  include <pstl/glue_numeric_impl.h># else// Otherwise just pull in forward declarations#  include <pstl/glue_numeric_defs.h>#  define __PSTL_NUMERIC_FORWARD_DECLARED 1# endif// Feature test macro for parallel algorithms# define __cpp_lib_parallel_algorithm 201603L#endif // C++17#endif /* _GLIBCXX_NUMERIC */
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