标准库标头 <algorithm>

来自cppreference.com
< cpp‎ | header
 
C++
 
标准库标头
注：修订记号中的反斜杠 '/' 意味着此标头被弃用和/或被移除。
语言支持
概念
<concepts> (C++20)
诊断
<system_error> (C++11)
内存管理
<memory_resource> (C++17)  
元编程
<type_traits> (C++11)
<ratio> (C++11)
通用工具
<utility>
<tuple> (C++11)
<optional> (C++17)
<variant> (C++17)
<any> (C++17)
<expected> (C++23)
<bitset>

<charconv> (C++17)
<format> (C++20)
<bit> (C++20)

字符串
<cuchar> (C++11)

容器
<flat_set> (C++23)
<span> (C++20)
<mdspan> (C++23)

迭代器
<iterator>
范围
<ranges> (C++20)
<generator> (C++23)
算法
<algorithm>
数值
<cfenv> (C++11)
<complex>
<numbers> (C++20)

日期时间
<chrono> (C++11)
本地化
<codecvt> (C++11/17)
输入/输出
<filesystem> (C++17)
<cstdio>
<cinttypes> (C++11)
<strstream> (C++98/)
正则表达式
<regex>
并发支持
<stop_token> (C++20)
<thread> (C++11)
<atomic> (C++11)
<stdatomic.h> (C++23)
<mutex> (C++11)
<shared_mutex> (C++14)
<condition_variable> (C++11)  
<semaphore> (C++20)
<latch> (C++20)
<barrier> (C++20)
<future> (C++11)

C 兼容
<cstdbool> (C++11/17/20)  
<ccomplex> (C++11/17/20)
<ctgmath> (C++11/17/20)

<cstdalign> (C++11/17/20)

<ciso646> (C++20 前)

 

此头文件是算法库的一部分。

包含

(C++11)
 std::initializer_list 类模板

类

在命名空间 std::ranges 定义
返回类型
(C++20)
 提供存储一个迭代器与一个函数对象为单个单元的方式
(类模板)
(C++20)
 提供存储二个迭代器为单个单元的方式
(类模板)
(C++20)
 提供存储二个迭代器为单个单元的方式
(类模板)
(C++20)
 提供存储三个迭代器为单个单元的方式
(类模板)
(C++20)
 提供存储三个迭代器为单个单元的方式
(类模板)
(C++20)
 提供存储二个同类型对象或引用为单个单元的方式
(类模板)
(C++20)
 提供存储一个迭代器与一个布尔标志为单个单元的方式
(类模板)

函数

不修改序列的操作
(C++11)(C++11)(C++11)
 检查谓词是否对范围中所有、任一或无元素为 true
(函数模板)
应用函数到范围中的元素
(函数模板)
(C++17)
 应用一个函数对象到序列的前 n 个元素
(函数模板)
返回满足指定判别标准的元素数
(函数模板)
寻找两个范围出现不同的首个位置
(函数模板)
(C++11)
 寻找首个满足特定判别标准的元素
(函数模板)
在特定范围中寻找最后出现的元素序列
(函数模板)
搜索元素集合中的任意元素
(函数模板)
查找首对相邻的相同（或满足给定谓词的）元素
(函数模板)
搜索一个元素范围
(函数模板)
在范围中搜索一定量的某个元素的连续副本
(函数模板)
修改序列的操作
(C++11)
 将某一范围的元素复制到一个新的位置
(函数模板)
(C++11)
 将一定数目的元素复制到一个新的位置
(函数模板)
按从后往前的顺序复制一个范围内的元素
(函数模板)
(C++11)
 将某一范围的元素移动到一个新的位置
(函数模板)
(C++11)
 按从后往前的顺序移动某一范围的元素到新的位置
(函数模板)
将一个给定值复制赋值给一个范围内的每个元素
(函数模板)
将一个给定值复制赋值给一个范围内的 N 个元素
(函数模板)
将一个函数应用于某一范围的各个元素，并在目标范围存储结果
(函数模板)
将相继的函数调用结果赋值给一个范围中的每个元素
(函数模板)
将相继的函数调用结果赋值给一个范围中的 N 个元素
(函数模板)
移除满足特定判别标准的元素
(函数模板)
复制一个范围的元素，忽略满足特定判别标准的元素
(函数模板)
将所有满足特定判别标准的值替换为另一个值
(函数模板)
复制一个范围内的元素，并将满足特定判别标准的元素替换为另一个值
(函数模板)
交换两个对象的值
(函数模板)
交换两个范围的元素
(函数模板)
交换两个迭代器所指向的元素
(函数模板)
逆转范围中的元素顺序
(函数模板)
创建一个范围的逆向副本
(函数模板)
旋转范围中的元素顺序
(函数模板)
复制并旋转元素范围
(函数模板)
(C++20)
 迁移范围中的元素
(函数模板)
(C++17 前)(C++11)
 随机重排范围中的元素
(函数模板)
(C++17)
 从一个序列中随机选择 n 个元素
(函数模板)
移除范围内的连续重复元素
(函数模板)
创建某范围的不含连续重复元素的副本
(函数模板)
划分操作
(C++11)
 判断范围是否已按给定的谓词划分
(函数模板)
将范围中的元素分为两组
(函数模板)
(C++11)
 复制一个范围，将各元素分为两组
(函数模板)
将元素分为两组，同时保留其相对顺序
(函数模板)
(C++11)
 定位已划分范围的划分点
(函数模板)
排序操作
(C++11)
 检查范围是否已按升序排列
(函数模板)
(C++11)
 找出最大的已排序子范围
(函数模板)
将范围按升序排序
(函数模板)
排序一个范围的前 N 个元素
(函数模板)
对范围内的元素进行复制并部分排序
(函数模板)
将范围内的元素排序，同时保持相等的元素之间的顺序
(函数模板)
将给定的范围部分排序，确保其按给定元素划分
(函数模板)
（已排序范围上的）二分搜索操作
返回指向第一个不小于给定值的元素的迭代器
(函数模板)
返回指向第一个大于给定值的元素的迭代器
(函数模板)
确定元素是否存在于某范围中
(函数模板)
返回匹配特定键值的元素范围
(函数模板)
其他已排序范围上的操作
归并两个有序范围
(函数模板)
就地归并两个有序范围
(函数模板)
（已排序范围上的）集合操作
若一个序列是另一个的子列则返回 true
(函数模板)
计算两个集合的差集
(函数模板)
计算两个集合的交集
(函数模板)
计算两个集合的对称差
(函数模板)
计算两个集合的并集
(函数模板)
堆操作
检查给定范围是否为一个最大堆
(函数模板)
(C++11)
 查找能成为最大堆的最大子范围
(函数模板)
从一个元素范围创建出一个最大堆
(函数模板)
将一个元素加入到一个最大堆
(函数模板)
从最大堆中移除最大元素
(函数模板)
将一个最大堆变成一个按升序排序的元素范围
(函数模板)
最小/最大操作
返回各给定值中的较大者
(函数模板)
返回范围内的最大元素
(函数模板)
返回各给定值中的较小者
(函数模板)
返回范围内的最小元素
(函数模板)
(C++11)
 返回两个元素的较小和较大者
(函数模板)
(C++11)
 返回范围内的最小元素和最大元素
(函数模板)
(C++17)
 在一对边界值间夹逼一个值
(函数模板)
比较操作
确定两个元素集合是否是相同的
(函数模板)
当一个范围按字典顺序小于另一个范围时，返回 true
(函数模板)
(C++20)
 用三路比较比较两个范围
(函数模板)
排列操作
(C++11)
 判断一个序列是否为另一个序列的排列
(函数模板)
产生某个元素范围的按字典顺序的下一个较大的排列
(函数模板)
产生某个元素范围的按字典顺序的下一个较小的排列
(函数模板)

仿函数实体

在命名空间 std::ranges 定义
不修改序列的操作
(C++20)(C++20)(C++20)
 检查谓词是否对范围中所有、任一或无元素为 true
(niebloid)
(C++20)
 应用函数到范围中的元素
(niebloid)
(C++20)
 应用函数对象到序列的首 n 个元素
(niebloid)
(C++20)(C++20)
 返回满足指定判别标准的元素数
(niebloid)
(C++20)
 寻找两个范围出现不同的首个位置
(niebloid)
(C++20)(C++20)(C++20)
 查找满足特定条件的的第一个元素
(niebloid)
(C++20)
 查找特定范围中最后出现的元素序列
(niebloid)
(C++20)
 查找元素集合中的任一元素
(niebloid)
(C++20)
 查找首对相邻的相同（或满足给定谓词的）元素
(niebloid)
(C++20)
 搜索一个元素范围
(niebloid)
(C++20)
 在范围中搜索一定量的某个元素的连续副本
(niebloid)
(C++23)
 检查一个范围是否始于另一范围
(niebloid)
(C++23)
 检查一个范围是否终于另一范围
(niebloid)
修改序列的操作
(C++20)(C++20)
 将某一范围的元素复制到一个新的位置
(niebloid)
(C++20)
 将一定数目的元素复制到一个新的位置
(niebloid)
(C++20)
 按从后往前的顺序复制一个范围内的元素
(niebloid)
(C++20)
 将某一范围的元素移动到一个新的位置
(niebloid)
(C++20)
 按从后往前的顺序移动某一范围的元素到新的位置
(niebloid)
(C++20)
 将一个给定值复制赋值给一个范围内的每个元素
(niebloid)
(C++20)
 将一个值复制赋值给一定量的元素
(niebloid)
(C++20)
 将一个函数应用于某一范围的各个元素
(niebloid)
(C++20)
 保存函数结果到一个范围中
(niebloid)
(C++20)
 保存 N 次函数应用的结果
(niebloid)
(C++20)(C++20)
 移除满足特定判别标准的元素
(niebloid)
(C++20)(C++20)
 复制一个范围的元素，忽略满足特定判别标准的元素
(niebloid)
(C++20)(C++20)
 将所有满足特定判别标准的值替换为另一个值
(niebloid)
(C++20)(C++20)
 复制一个范围内的元素，并将满足特定判别标准的元素替换为另一个值
(niebloid)
(C++20)
 交换两个范围的元素
(niebloid)
(C++20)
 逆转范围中的元素顺序
(niebloid)
(C++20)
 创建一个范围的逆向副本
(niebloid)
(C++20)
 旋转范围中的元素顺序
(niebloid)
(C++20)
 复制并旋转元素范围
(niebloid)
(C++20)
 从序列中随机选择 n 个元素
(niebloid)
(C++20)
 随机重排范围中的元素
(niebloid)
(C++20)
 移除范围中的连续重复元素
(niebloid)
(C++20)
 创建某范围的不含连续重复元素的副本
(niebloid)
划分操作
(C++20)
 判断范围是否已按给定的谓词划分
(niebloid)
(C++20)
 将范围中的元素分为二组
(niebloid)
(C++20)
 复制一个范围，将各元素分为二组
(niebloid)
(C++20)
 将元素分成二组，同时保持其相对顺序
(niebloid)
(C++20)
 定位已划分范围的划分点
(niebloid)
排序操作
(C++20)
 检查范围是否以升序排序
(niebloid)
(C++20)
 寻找最大的已排序子范围
(niebloid)
(C++20)
 将范围按升序排序
(niebloid)
(C++20)
 排序一个范围的前 N 个元素
(niebloid)
(C++20)
 对范围内的元素进行复制并部分排序
(niebloid)
(C++20)
 将范围内的元素排序，同时保持相等的元素之间的顺序
(niebloid)
(C++20)
 将给定的范围部分排序，确保其按给定元素划分
(niebloid)
（已排序范围上的）集合操作
(C++20)
 返回指向首个不小于给定值的元素的迭代器
(niebloid)
(C++20)
 返回指向首个大于某值的元素的迭代器
(niebloid)
(C++20)
 确定元素是否存在于某范围中
(niebloid)
(C++20)
 返回匹配特定值的元素范围
(niebloid)
其他已排序范围上的操作
(C++20)
 归并两个有序范围
(niebloid)
(C++20)
 在原位归并两个有序范围
(niebloid)
（已排序范围上的）集合操作
(C++20)
 若一个序列是另一个的子列则返回 true
(niebloid)
(C++20)
 计算两个集合的差集
(niebloid)
(C++20)
 计算两个集合的交集
(niebloid)
(C++20)
 计算两个集合的对称差
(niebloid)
(C++20)
 计算两个集合的并集
(niebloid)
堆操作
(C++20)
 检查给定范围是否为最大堆
(niebloid)
(C++20)
 寻找能成为最大堆的最大子范围
(niebloid)
(C++20)
 从一个元素范围创建出一个最大堆
(niebloid)
(C++20)
 将一个元素加入到一个最大堆
(niebloid)
(C++20)
 从最大堆中移除最大元素
(niebloid)
(C++20)
 将一个最大堆变成一个按升序排序的元素范围
(niebloid)
最小/最大操作
(C++20)
 返回给定值的较大者
(niebloid)
(C++20)
 返回范围中的最大元素
(niebloid)
(C++20)
 返回给定值的较小者
(niebloid)
(C++20)
 返回范围中的最小元素
(niebloid)
(C++20)
 返回两个元素的较小和较大者
(niebloid)
(C++20)
 返回范围中的最小和最大元素
(niebloid)
(C++20)
 在一对边界值间夹一个值
(niebloid)
比较操作
(C++20)
 确定两个元素集合是否是相同的
(niebloid)
(C++20)
 当一个范围按字典顺序小于另一个范围时，返回 true
(niebloid)
排列操作
(C++20)
 确定一个序列是否为另一序列的重排
(niebloid)
(C++20)
 产生某个元素范围的按字典序下一个较大的排列
(niebloid)

概要

#include <initializer_list>
 
namespace std {
  namespace ranges {
    // 算法结果类型
    template<class I, class F> struct in_fun_result;
    template<class I1, class I2> struct in_in_result;
    template<class I, class O> struct in_out_result;
    template<class I1, class I2, class O> struct in_in_out_result;
    template<class I, class O1, class O2> struct in_out_out_result;
    template<class T> struct min_max_result;
    template<class I> struct in_found_result;
  }
 
  // 不修改序列的操作
  // 全部
  template<class InputIter, class Pred>
    constexpr bool all_of(InputIter first, InputIter last, Pred pred);
  template<class ExecutionPolicy, class ForwardIter, class Pred>
    bool all_of(ExecutionPolicy&& exec,
                ForwardIter first, ForwardIter last, Pred pred);
 
  namespace ranges {
    template<input_iterator I, sentinel_for<I> S, class Proj = identity,
             indirect_unary_predicate<projected<I, Proj>> Pred>
      constexpr bool all_of(I first, S last, Pred pred, Proj proj = {});
    template<input_range R, class Proj = identity,
             indirect_unary_predicate<projected<iterator_t<R>, Proj>> Pred>
      constexpr bool all_of(R&& r, Pred pred, Proj proj = {});
  }
 
  // 任何
  template<class InputIter, class Pred>
    constexpr bool any_of(InputIter first, InputIter last, Pred pred);
  template<class ExecutionPolicy, class ForwardIter, class Pred>
    bool any_of(ExecutionPolicy&& exec,
                ForwardIter first, ForwardIter last, Pred pred);
 
  namespace ranges {
    template<input_iterator I, sentinel_for<I> S, class Proj = identity,
             indirect_unary_predicate<projected<I, Proj>> Pred>
      constexpr bool any_of(I first, S last, Pred pred, Proj proj = {});
    template<input_range R, class Proj = identity,
             indirect_unary_predicate<projected<iterator_t<R>, Proj>> Pred>
      constexpr bool any_of(R&& r, Pred pred, Proj proj = {});
  }
 
  // 无一
  template<class InputIter, class Pred>
    constexpr bool none_of(InputIter first, InputIter last, Pred pred);
  template<class ExecutionPolicy, class ForwardIter, class Pred>
    bool none_of(ExecutionPolicy&& exec,
                 ForwardIter first, ForwardIter last, Pred pred);
 
  namespace ranges {
    template<input_iterator I, sentinel_for<I> S, class Proj = identity,
             indirect_unary_predicate<projected<I, Proj>> Pred>
      constexpr bool none_of(I first, S last, Pred pred, Proj proj = {});
    template<input_range R, class Proj = identity,
             indirect_unary_predicate<projected<iterator_t<R>, Proj>> Pred>
      constexpr bool none_of(R&& r, Pred pred, Proj proj = {});
  }
 
  // 对每个
  template<class InputIter, class Function>
    constexpr Function for_each(InputIter first, InputIter last, Function f);
  template<class ExecutionPolicy, class ForwardIter, class Function>
    void for_each(ExecutionPolicy&& exec,
                  ForwardIter first, ForwardIter last, Function f);
 
  namespace ranges {
    template<class I, class F>
      using for_each_result = in_fun_result<I, F>;
 
    template<input_iterator I, sentinel_for<I> S, class Proj = identity,
             indirectly_unary_invocable<projected<I, Proj>> Fun>
      constexpr for_each_result<I, Fun>
        for_each(I first, S last, Fun f, Proj proj = {});
    template<input_range R, class Proj = identity,
             indirectly_unary_invocable<projected<iterator_t<R>, Proj>> Fun>
      constexpr for_each_result<borrowed_iterator_t<R>, Fun>
        for_each(R&& r, Fun f, Proj proj = {});
  }
 
  template<class InputIter, class Size, class Function>
    constexpr InputIter for_each_n(InputIter first, Size n, Function f);
  template<class ExecutionPolicy, class ForwardIter, class Size, class Function>
    ForwardIter for_each_n(ExecutionPolicy&& exec,
                               ForwardIter first, Size n, Function f);
 
  namespace ranges {
    template<class I, class F>
      using for_each_n_result = in_fun_result<I, F>;
 
    template<input_iterator I, class Proj = identity,
             indirectly_unary_invocable<projected<I, Proj>> Fun>
      constexpr for_each_n_result<I, Fun>
        for_each_n(I first, iter_difference_t<I> n, Fun f, Proj proj = {});
  }
 
  // 寻找
  template<class InputIter, class T>
    constexpr InputIter find(InputIter first, InputIter last,
                                 const T& value);
  template<class ExecutionPolicy, class ForwardIter, class T>
    ForwardIter find(ExecutionPolicy&& exec,
                         ForwardIter first, ForwardIter last,
                         const T& value);
  template<class InputIter, class Pred>
    constexpr InputIter find_if(InputIter first, InputIter last,
                                    Pred pred);
  template<class ExecutionPolicy, class ForwardIter, class Pred>
    ForwardIter find_if(ExecutionPolicy&& exec,
                            ForwardIter first, ForwardIter last,
                            Pred pred);
  template<class InputIter, class Pred>
    constexpr InputIter find_if_not(InputIter first, InputIter last,
                                        Pred pred);
  template<class ExecutionPolicy, class ForwardIter, class Pred>
    ForwardIter find_if_not(ExecutionPolicy&& exec,
                                ForwardIter first, ForwardIter last,
                                Pred pred);
 
  namespace ranges {
    template<input_iterator I, sentinel_for<I> S, class T, class Proj = identity>
      requires indirect_binary_predicate<ranges::equal_to, projected<I, Proj>, const T*>
      constexpr I find(I first, S last, const T& value, Proj proj = {});
    template<input_range R, class T, class Proj = identity>
      requires indirect_binary_predicate<ranges::equal_to,
                                         projected<iterator_t<R>, Proj>, const T*>
      constexpr borrowed_iterator_t<R>
        find(R&& r, const T& value, Proj proj = {});
    template<input_iterator I, sentinel_for<I> S, class Proj = identity,
             indirect_unary_predicate<projected<I, Proj>> Pred>
      constexpr I find_if(I first, S last, Pred pred, Proj proj = {});
    template<input_range R, class Proj = identity,
             indirect_unary_predicate<projected<iterator_t<R>, Proj>> Pred>
      constexpr borrowed_iterator_t<R>
        find_if(R&& r, Pred pred, Proj proj = {});
    template<input_iterator I, sentinel_for<I> S, class Proj = identity,
             indirect_unary_predicate<projected<I, Proj>> Pred>
      constexpr I find_if_not(I first, S last, Pred pred, Proj proj = {});
    template<input_range R, class Proj = identity,
             indirect_unary_predicate<projected<iterator_t<R>, Proj>> Pred>
      constexpr borrowed_iterator_t<R>
        find_if_not(R&& r, Pred pred, Proj proj = {});
  }
 
  // 寻找末尾
  template<class ForwardIter1, class ForwardIter2>
    constexpr ForwardIter1
      find_end(ForwardIter1 first1, ForwardIter1 last1,
               ForwardIter2 first2, ForwardIter2 last2);
  template<class ForwardIter1, class ForwardIter2, class BinaryPred>
    constexpr ForwardIter1
      find_end(ForwardIter1 first1, ForwardIter1 last1,
               ForwardIter2 first2, ForwardIter2 last2,
               BinaryPred pred);
  template<class ExecutionPolicy, class ForwardIter1, class ForwardIter2>
    ForwardIter1
      find_end(ExecutionPolicy&& exec,
               ForwardIter1 first1, ForwardIter1 last1,
               ForwardIter2 first2, ForwardIter2 last2);
  template<class ExecutionPolicy, class ForwardIter1,
           class ForwardIter2, class BinaryPred>
    ForwardIter1
      find_end(ExecutionPolicy&& exec,
               ForwardIter1 first1, ForwardIter1 last1,
               ForwardIter2 first2, ForwardIter2 last2,
               BinaryPred pred);
 
  namespace ranges {
    template<forward_iterator I1, sentinel_for<I1> S1, forward_iterator I2, sentinel_for<I2> S2,
             class Pred = ranges::equal_to, class Proj1 = identity, class Proj2 = identity>
      requires indirectly_comparable<I1, I2, Pred, Proj1, Proj2>
      constexpr subrange<I1>
        find_end(I1 first1, S1 last1, I2 first2, S2 last2, Pred pred = {},
                 Proj1 proj1 = {}, Proj2 proj2 = {});
    template<forward_range R1, forward_range R2,
             class Pred = ranges::equal_to, class Proj1 = identity, class Proj2 = identity>
      requires indirectly_comparable<iterator_t<R1>, iterator_t<R2>, Pred, Proj1, Proj2>
      constexpr borrowed_subrange_t<R1>
        find_end(R1&& r1, R2&& r2, Pred pred = {},
                 Proj1 proj1 = {}, Proj2 proj2 = {});
  }
 
  // 寻找首个
  template<class InputIter, class ForwardIter>
    constexpr InputIter
      find_first_of(InputIter first1, InputIter last1,
                    ForwardIter first2, ForwardIter last2);
  template<class InputIter, class ForwardIter, class BinaryPred>
    constexpr InputIter
      find_first_of(InputIter first1, InputIter last1,
                    ForwardIter first2, ForwardIter last2,
                    BinaryPred pred);
  template<class ExecutionPolicy, class ForwardIter1, class ForwardIter2>
    ForwardIter1
      find_first_of(ExecutionPolicy&& exec,
                    ForwardIter1 first1, ForwardIter1 last1,
                    ForwardIter2 first2, ForwardIter2 last2);
  template<class ExecutionPolicy, class ForwardIter1,
           class ForwardIter2, class BinaryPred>
    ForwardIter1
      find_first_of(ExecutionPolicy&& exec,
                    ForwardIter1 first1, ForwardIter1 last1,
                    ForwardIter2 first2, ForwardIter2 last2,
                    BinaryPred pred);
 
  namespace ranges {
    template<input_iterator I1, sentinel_for<I1> S1, forward_iterator I2, sentinel_for<I2> S2,
             class Pred = ranges::equal_to, class Proj1 = identity, class Proj2 = identity>
      requires indirectly_comparable<I1, I2, Pred, Proj1, Proj2>
      constexpr I1 find_first_of(I1 first1, S1 last1, I2 first2, S2 last2, Pred pred = {},
                                 Proj1 proj1 = {}, Proj2 proj2 = {});
    template<input_range R1, forward_range R2,
             class Pred = ranges::equal_to, class Proj1 = identity, class Proj2 = identity>
      requires indirectly_comparable<iterator_t<R1>, iterator_t<R2>, Pred, Proj1, Proj2>
      constexpr borrowed_iterator_t<R1>
        find_first_of(R1&& r1, R2&& r2, Pred pred = {},
                      Proj1 proj1 = {}, Proj2 proj2 = {});
  }
 
  // 寻找毗邻
  template<class ForwardIter>
    constexpr ForwardIter
      adjacent_find(ForwardIter first, ForwardIter last);
  template<class ForwardIter, class BinaryPred>
    constexpr ForwardIter
      adjacent_find(ForwardIter first, ForwardIter last,
                    BinaryPred pred);
  template<class ExecutionPolicy, class ForwardIter>
    ForwardIter
      adjacent_find(ExecutionPolicy&& exec,
                    ForwardIter first, ForwardIter last);
  template<class ExecutionPolicy, class ForwardIter, class BinaryPred>
    ForwardIter
      adjacent_find(ExecutionPolicy&& exec,
                    ForwardIter first, ForwardIter last,
                    BinaryPred pred);
 
  namespace ranges {
    template<forward_iterator I, sentinel_for<I> S, class Proj = identity,
             indirect_binary_predicate<projected<I, Proj>,
                                       projected<I, Proj>> Pred = ranges::equal_to>
      constexpr I adjacent_find(I first, S last, Pred pred = {},
                                Proj proj = {});
    template<forward_range R, class Proj = identity,
             indirect_binary_predicate<projected<iterator_t<R>, Proj>,
                                       projected<iterator_t<R>, Proj>> Pred = ranges::equal_to>
      constexpr borrowed_iterator_t<R>
        adjacent_find(R&& r, Pred pred = {}, Proj proj = {});
  }
 
  // 计数
  template<class InputIter, class T>
    constexpr typename iterator_traits<InputIter>::difference_type
      count(InputIter first, InputIter last, const T& value);
  template<class ExecutionPolicy, class ForwardIter, class T>
    typename iterator_traits<ForwardIter>::difference_type
      count(ExecutionPolicy&& exec,
            ForwardIter first, ForwardIter last, const T& value);
  template<class InputIter, class Pred>
    constexpr typename iterator_traits<InputIter>::difference_type
      count_if(InputIter first, InputIter last, Pred pred);
  template<class ExecutionPolicy, class ForwardIter, class Pred>
    typename iterator_traits<ForwardIter>::difference_type
      count_if(ExecutionPolicy&& exec,
               ForwardIter first, ForwardIter last, Pred pred);
 
  namespace ranges {
    template<input_iterator I, sentinel_for<I> S, class T, class Proj = identity>
      requires indirect_binary_predicate<ranges::equal_to, projected<I, Proj>, const T*>
      constexpr iter_difference_t<I>
        count(I first, S last, const T& value, Proj proj = {});
    template<input_range R, class T, class Proj = identity>
      requires indirect_binary_predicate<ranges::equal_to,
                                         projected<iterator_t<R>, Proj>, const T*>
      constexpr range_difference_t<R>
        count(R&& r, const T& value, Proj proj = {});
    template<input_iterator I, sentinel_for<I> S, class Proj = identity,
             indirect_unary_predicate<projected<I, Proj>> Pred>
      constexpr iter_difference_t<I>
        count_if(I first, S last, Pred pred, Proj proj = {});
    template<input_range R, class Proj = identity,
             indirect_unary_predicate<projected<iterator_t<R>, Proj>> Pred>
      constexpr range_difference_t<R>
        count_if(R&& r, Pred pred, Proj proj = {});
  }
 
  // 不匹配
  template<class InputIter1, class InputIter2>
    constexpr pair<InputIter1, InputIter2>
      mismatch(InputIter1 first1, InputIter1 last1,
               InputIter2 first2);
  template<class InputIter1, class InputIter2, class BinaryPred>
    constexpr pair<InputIter1, InputIter2>
      mismatch(InputIter1 first1, InputIter1 last1,
               InputIter2 first2, BinaryPred pred);
  template<class InputIter1, class InputIter2>
    constexpr pair<InputIter1, InputIter2>
      mismatch(InputIter1 first1, InputIter1 last1,
               InputIter2 first2, InputIter2 last2);
  template<class InputIter1, class InputIter2, class BinaryPred>
    constexpr pair<InputIter1, InputIter2>
      mismatch(InputIter1 first1, InputIter1 last1,
               InputIter2 first2, InputIter2 last2,
               BinaryPred pred);
  template<class ExecutionPolicy, class ForwardIter1, class ForwardIter2>
    pair<ForwardIter1, ForwardIter2>
      mismatch(ExecutionPolicy&& exec,
               ForwardIter1 first1, ForwardIter1 last1,
               ForwardIter2 first2);
  template<class ExecutionPolicy, class ForwardIter1, class ForwardIter2,
           class BinaryPred>
    pair<ForwardIter1, ForwardIter2>
      mismatch(ExecutionPolicy&& exec,
               ForwardIter1 first1, ForwardIter1 last1,
               ForwardIter2 first2, BinaryPred pred);
  template<class ExecutionPolicy, class ForwardIter1, class ForwardIter2>
    pair<ForwardIter1, ForwardIter2>
      mismatch(ExecutionPolicy&& exec,
               ForwardIter1 first1, ForwardIter1 last1,
               ForwardIter2 first2, ForwardIter2 last2);
  template<class ExecutionPolicy, class ForwardIter1, class ForwardIter2,
           class BinaryPred>
    pair<ForwardIter1, ForwardIter2>
      mismatch(ExecutionPolicy&& exec,
               ForwardIter1 first1, ForwardIter1 last1,
               ForwardIter2 first2, ForwardIter2 last2,
               BinaryPred pred);
 
  namespace ranges {
    template<class I1, class I2>
      using mismatch_result = in_in_result<I1, I2>;
 
    template<input_iterator I1, sentinel_for<I1> S1, input_iterator I2, sentinel_for<I2> S2,
             class Pred = ranges::equal_to, class Proj1 = identity, class Proj2 = identity>
      requires indirectly_comparable<I1, I2, Pred, Proj1, Proj2>
      constexpr mismatch_result<I1, I2>
        mismatch(I1 first1, S1 last1, I2 first2, S2 last2, Pred pred = {},
                 Proj1 proj1 = {}, Proj2 proj2 = {});
    template<input_range R1, input_range R2,
             class Pred = ranges::equal_to, class Proj1 = identity, class Proj2 = identity>
      requires indirectly_comparable<iterator_t<R1>, iterator_t<R2>, Pred, Proj1, Proj2>
      constexpr mismatch_result<borrowed_iterator_t<R1>, borrowed_iterator_t<R2>>
        mismatch(R1&& r1, R2&& r2, Pred pred = {},
                 Proj1 proj1 = {}, Proj2 proj2 = {});
  }
 
  // 相等
  template<class InputIter1, class InputIter2>
    constexpr bool equal(InputIter1 first1, InputIter1 last1,
                         InputIter2 first2);
  template<class InputIter1, class InputIter2, class BinaryPred>
    constexpr bool equal(InputIter1 first1, InputIter1 last1,
                         InputIter2 first2, BinaryPred pred);
  template<class InputIter1, class InputIter2>
    constexpr bool equal(InputIter1 first1, InputIter1 last1,
                         InputIter2 first2, InputIter2 last2);
  template<class InputIter1, class InputIter2, class BinaryPred>
    constexpr bool equal(InputIter1 first1, InputIter1 last1,
                         InputIter2 first2, InputIter2 last2,
                         BinaryPred pred);
  template<class ExecutionPolicy, class ForwardIter1, class ForwardIter2>
    bool equal(ExecutionPolicy&& exec,
               ForwardIter1 first1, ForwardIter1 last1,
               ForwardIter2 first2);
  template<class ExecutionPolicy, class ForwardIter1, class ForwardIter2,
           class BinaryPred>
    bool equal(ExecutionPolicy&& exec,
               ForwardIter1 first1, ForwardIter1 last1,
               ForwardIter2 first2, BinaryPred pred);
  template<class ExecutionPolicy, class ForwardIter1, class ForwardIter2>
    bool equal(ExecutionPolicy&& exec,
               ForwardIter1 first1, ForwardIter1 last1,
               ForwardIter2 first2, ForwardIter2 last2);
  template<class ExecutionPolicy, class ForwardIter1, class ForwardIter2,
           class BinaryPred>
    bool equal(ExecutionPolicy&& exec,
               ForwardIter1 first1, ForwardIter1 last1,
               ForwardIter2 first2, ForwardIter2 last2,
               BinaryPred pred);
 
  namespace ranges {
    template<input_iterator I1, sentinel_for<I1> S1, input_iterator I2, sentinel_for<I2> S2,
             class Pred = ranges::equal_to, class Proj1 = identity, class Proj2 = identity>
      requires indirectly_comparable<I1, I2, Pred, Proj1, Proj2>
      constexpr bool equal(I1 first1, S1 last1, I2 first2, S2 last2,
                           Pred pred = {},
                           Proj1 proj1 = {}, Proj2 proj2 = {});
    template<input_range R1, input_range R2, class Pred = ranges::equal_to,
             class Proj1 = identity, class Proj2 = identity>
      requires indirectly_comparable<iterator_t<R1>, iterator_t<R2>, Pred, Proj1, Proj2>
      constexpr bool equal(R1&& r1, R2&& r2, Pred pred = {},
                           Proj1 proj1 = {}, Proj2 proj2 = {});
  }
 
  // 为排列
  template<class ForwardIter1, class ForwardIter2>
    constexpr bool is_permutation(ForwardIter1 first1, ForwardIter1 last1,
                                  ForwardIter2 first2);
  template<class ForwardIter1, class ForwardIter2, class BinaryPred>
    constexpr bool is_permutation(ForwardIter1 first1, ForwardIter1 last1,
                                  ForwardIter2 first2, BinaryPred pred);
  template<class ForwardIter1, class ForwardIter2>
    constexpr bool is_permutation(ForwardIter1 first1, ForwardIter1 last1,
                                  ForwardIter2 first2, ForwardIter2 last2);
  template<class ForwardIter1, class ForwardIter2, class BinaryPred>
    constexpr bool is_permutation(ForwardIter1 first1, ForwardIter1 last1,
                                  ForwardIter2 first2, ForwardIter2 last2,
                                  BinaryPred pred);
 
  namespace ranges {
    template<forward_iterator I1, sentinel_for<I1> S1, forward_iterator I2,
             sentinel_for<I2> S2, class Proj1 = identity, class Proj2 = identity,
             indirect_equivalence_relation<projected<I1, Proj1>,
                                           projected<I2, Proj2>> Pred = ranges::equal_to>
      constexpr bool is_permutation(I1 first1, S1 last1, I2 first2, S2 last2,
                                    Pred pred = {},
                                    Proj1 proj1 = {}, Proj2 proj2 = {});
    template<forward_range R1, forward_range R2,
             class Proj1 = identity, class Proj2 = identity,
             indirect_equivalence_relation<projected<iterator_t<R1>, Proj1>,
                                           projected<iterator_t<R2>, Proj2>>
               Pred = ranges::equal_to>
      constexpr bool is_permutation(R1&& r1, R2&& r2, Pred pred = {},
                                    Proj1 proj1 = {}, Proj2 proj2 = {});
  }
 
  // 搜索
  template<class ForwardIter1, class ForwardIter2>
    constexpr ForwardIter1
      search(ForwardIter1 first1, ForwardIter1 last1,
             ForwardIter2 first2, ForwardIter2 last2);
  template<class ForwardIter1, class ForwardIter2, class BinaryPred>
    constexpr ForwardIter1
      search(ForwardIter1 first1, ForwardIter1 last1,
             ForwardIter2 first2, ForwardIter2 last2,
             BinaryPred pred);
  template<class ExecutionPolicy, class ForwardIter1, class ForwardIter2>
    ForwardIter1
      search(ExecutionPolicy&& exec,
             ForwardIter1 first1, ForwardIter1 last1,
             ForwardIter2 first2, ForwardIter2 last2);
  template<class ExecutionPolicy, class ForwardIter1, class ForwardIter2,
           class BinaryPred>
    ForwardIter1
      search(ExecutionPolicy&& exec,
             ForwardIter1 first1, ForwardIter1 last1,
             ForwardIter2 first2, ForwardIter2 last2,
             BinaryPred pred);
 
  namespace ranges {
    template<forward_iterator I1, sentinel_for<I1> S1, forward_iterator I2,
             sentinel_for<I2> S2, class Pred = ranges::equal_to,
             class Proj1 = identity, class Proj2 = identity>
      requires indirectly_comparable<I1, I2, Pred, Proj1, Proj2>
      constexpr subrange<I1>
        search(I1 first1, S1 last1, I2 first2, S2 last2, Pred pred = {},
               Proj1 proj1 = {}, Proj2 proj2 = {});
    template<forward_range R1, forward_range R2, class Pred = ranges::equal_to,
             class Proj1 = identity, class Proj2 = identity>
      requires indirectly_comparable<iterator_t<R1>, iterator_t<R2>, Pred, Proj1, Proj2>
      constexpr borrowed_subrange_t<R1>
        search(R1&& r1, R2&& r2, Pred pred = {},
               Proj1 proj1 = {}, Proj2 proj2 = {});
  }
 
  template<class ForwardIter, class Size, class T>
    constexpr ForwardIter
      search_n(ForwardIter first, ForwardIter last,
               Size count, const T& value);
  template<class ForwardIter, class Size, class T, class BinaryPred>
    constexpr ForwardIter
      search_n(ForwardIter first, ForwardIter last,
               Size count, const T& value, BinaryPred pred);
  template<class ExecutionPolicy, class ForwardIter, class Size, class T>
    ForwardIter
      search_n(ExecutionPolicy&& exec,
               ForwardIter first, ForwardIter last,
               Size count, const T& value);
  template<class ExecutionPolicy, class ForwardIter, class Size, class T,
           class BinaryPred>
    ForwardIter
      search_n(ExecutionPolicy&& exec,
               ForwardIter first, ForwardIter last,
               Size count, const T& value,
               BinaryPred pred);
 
  namespace ranges {
    template<forward_iterator I, sentinel_for<I> S, class T,
             class Pred = ranges::equal_to, class Proj = identity>
      requires indirectly_comparable<I, const T*, Pred, Proj>
      constexpr subrange<I>
        search_n(I first, S last, iter_difference_t<I> count,
                 const T& value, Pred pred = {}, Proj proj = {});
    template<forward_range R, class T, class Pred = ranges::equal_to,
             class Proj = identity>
      requires indirectly_comparable<iterator_t<R>, const T*, Pred, Proj>
      constexpr borrowed_subrange_t<R>
        search_n(R&& r, range_difference_t<R> count,
                 const T& value, Pred pred = {}, Proj proj = {});
  }
 
  template<class ForwardIter, class Searcher>
    constexpr ForwardIter
      search(ForwardIter first, ForwardIter last, const Searcher& searcher);
 
  namespace ranges {
    // 始于
    template<input_iterator I1, sentinel_for<I1> S1, input_iterator I2, sentinel_for<I2> S2,
             class Pred = ranges::equal_to, class Proj1 = identity, class Proj2 = identity>
      requires indirectly_comparable<I1, I2, Pred, Proj1, Proj2>
      constexpr bool starts_with(I1 first1, S1 last1, I2 first2, S2 last2, Pred pred = {},
                                 Proj1 proj1 = {}, Proj2 proj2 = {});
    template<input_range R1, input_range R2, class Pred = ranges::equal_to,
             class Proj1 = identity, class Proj2 = identity>
      requires indirectly_comparable<iterator_t<R1>, iterator_t<R2>, Pred, Proj1, Proj2>
      constexpr bool starts_with(R1&& r1, R2&& r2, Pred pred = {},
                                 Proj1 proj1 = {}, Proj2 proj2 = {});
 
    // 终于
    template<input_iterator I1, sentinel_for<I1> S1, input_iterator I2, sentinel_for<I2> S2,
             class Pred = ranges::equal_to, class Proj1 = identity, class Proj2 = identity>
      requires (forward_iterator<I1> || sized_sentinel_for<S1, I1>) &&
               (forward_iterator<I2> || sized_sentinel_for<S2, I2>) &&
               indirectly_comparable<I1, I2, Pred, Proj1, Proj2>
      constexpr bool ends_with(I1 first1, S1 last1, I2 first2, S2 last2, Pred pred = {},
                               Proj1 proj1 = {}, Proj2 proj2 = {});
    template<input_range R1, input_range R2, class Pred = ranges::equal_to,
             class Proj1 = identity, class Proj2 = identity>
      requires (forward_range<R1> || sized_range<R1>) &&
               (forward_range<R2> || sized_range<R2>) &&
               indirectly_comparable<iterator_t<R1>, iterator_t<R2>, Pred, Proj1, Proj2>
      constexpr bool ends_with(R1&& r1, R2&& r2, Pred pred = {},
                               Proj1 proj1 = {}, Proj2 proj2 = {});
  }
 
  // 修改序列的操作
  // 复制
  template<class InputIter, class OutputIter>
    constexpr OutputIter copy(InputIter first, InputIter last,
                                  OutputIter result);
  template<class ExecutionPolicy, class ForwardIter1, class ForwardIter2>
    ForwardIter2 copy(ExecutionPolicy&& exec,
                          ForwardIter1 first, ForwardIter1 last,
                          ForwardIter2 result);
 
  namespace ranges {
    template<class I, class O>
      using copy_result = in_out_result<I, O>;
 
    template<input_iterator I, sentinel_for<I> S, weakly_incrementable O>
      requires indirectly_copyable<I, O>
      constexpr copy_result<I, O>
        copy(I first, S last, O result);
    template<input_range R, weakly_incrementable O>
      requires indirectly_copyable<iterator_t<R>, O>
      constexpr copy_result<borrowed_iterator_t<R>, O>
        copy(R&& r, O result);
  }
 
  template<class InputIter, class Size, class OutputIter>
    constexpr OutputIter copy_n(InputIter first, Size n,
                                    OutputIter result);
  template<class ExecutionPolicy, class ForwardIter1, class Size,
           class ForwardIter2>
    ForwardIter2 copy_n(ExecutionPolicy&& exec,
                            ForwardIter1 first, Size n,
                            ForwardIter2 result);
 
  namespace ranges {
    template<class I, class O>
      using copy_n_result = in_out_result<I, O>;
 
    template<input_iterator I, weakly_incrementable O>
      requires indirectly_copyable<I, O>
      constexpr copy_n_result<I, O>
        copy_n(I first, iter_difference_t<I> n, O result);
  }
 
  template<class InputIter, class OutputIter, class Pred>
    constexpr OutputIter copy_if(InputIter first, InputIter last,
                                     OutputIter result, Pred pred);
  template<class ExecutionPolicy, class ForwardIter1, class ForwardIter2,
           class Pred>
    ForwardIter2 copy_if(ExecutionPolicy&& exec,
                             ForwardIter1 first, ForwardIter1 last,
                             ForwardIter2 result, Pred pred);
 
  namespace ranges {
    template<class I, class O>
      using copy_if_result = in_out_result<I, O>;
 
    template<input_iterator I, sentinel_for<I> S, weakly_incrementable O, class Proj = identity,
             indirect_unary_predicate<projected<I, Proj>> Pred>
      requires indirectly_copyable<I, O>
      constexpr copy_if_result<I, O>
        copy_if(I first, S last, O result, Pred pred, Proj proj = {});
    template<input_range R, weakly_incrementable O, class Proj = identity,
             indirect_unary_predicate<projected<iterator_t<R>, Proj>> Pred>
      requires indirectly_copyable<iterator_t<R>, O>
      constexpr copy_if_result<borrowed_iterator_t<R>, O>
        copy_if(R&& r, O result, Pred pred, Proj proj = {});
  }
 
  template<class BidirectionalIter1, class BidirectionalIter2>
    constexpr BidirectionalIter2
      copy_backward(BidirectionalIter1 first, BidirectionalIter1 last,
                    BidirectionalIter2 result);
 
  namespace ranges {
    template<class I1, class I2>
      using copy_backward_result = in_out_result<I1, I2>;
 
    template<bidirectional_iterator I1, sentinel_for<I1> S1, bidirectional_iterator I2>
      requires indirectly_copyable<I1, I2>
      constexpr copy_backward_result<I1, I2>
        copy_backward(I1 first, S1 last, I2 result);
    template<bidirectional_range R, bidirectional_iterator I>
      requires indirectly_copyable<iterator_t<R>, I>
      constexpr copy_backward_result<borrowed_iterator_t<R>, I>
        copy_backward(R&& r, I result);
  }
 
  // 移动
  template<class InputIter, class OutputIter>
    constexpr OutputIter move(InputIter first, InputIter last,
                                  OutputIter result);
  template<class ExecutionPolicy, class ForwardIter1,
           class ForwardIter2>
    ForwardIter2 move(ExecutionPolicy&& exec,
                          ForwardIter1 first, ForwardIter1 last,
                          ForwardIter2 result);
 
  namespace ranges {
    template<class I, class O>
      using move_result = in_out_result<I, O>;
 
    template<input_iterator I, sentinel_for<I> S, weakly_incrementable O>
      requires indirectly_movable<I, O>
      constexpr move_result<I, O>
        move(I first, S last, O result);
    template<input_range R, weakly_incrementable O>
      requires indirectly_movable<iterator_t<R>, O>
      constexpr move_result<borrowed_iterator_t<R>, O>
        move(R&& r, O result);
  }
 
  template<class BidirectionalIter1, class BidirectionalIter2>
    constexpr BidirectionalIter2
      move_backward(BidirectionalIter1 first, BidirectionalIter1 last,
                    BidirectionalIter2 result);
 
  namespace ranges {
    template<class I1, class I2>
      using move_backward_result = in_out_result<I1, I2>;
 
    template<bidirectional_iterator I1, sentinel_for<I1> S1, bidirectional_iterator I2>
      requires indirectly_movable<I1, I2>
      constexpr move_backward_result<I1, I2>
        move_backward(I1 first, S1 last, I2 result);
    template<bidirectional_range R, bidirectional_iterator I>
      requires indirectly_movable<iterator_t<R>, I>
      constexpr move_backward_result<borrowed_iterator_t<R>, I>
        move_backward(R&& r, I result);
  }
 
  // 交换
  template<class ForwardIter1, class ForwardIter2>
    constexpr ForwardIter2 swap_ranges(ForwardIter1 first1, ForwardIter1 last1,
                                           ForwardIter2 first2);
  template<class ExecutionPolicy, class ForwardIter1, class ForwardIter2>
    ForwardIter2 swap_ranges(ExecutionPolicy&& exec,
                                 ForwardIter1 first1, ForwardIter1 last1,
                                 ForwardIter2 first2);
 
  namespace ranges {
    template<class I1, class I2>
      using swap_ranges_result = in_in_result<I1, I2>;
 
    template<input_iterator I1, sentinel_for<I1> S1, input_iterator I2, sentinel_for<I2> S2>
      requires indirectly_swappable<I1, I2>
      constexpr swap_ranges_result<I1, I2>
        swap_ranges(I1 first1, S1 last1, I2 first2, S2 last2);
    template<input_range R1, input_range R2>
      requires indirectly_swappable<iterator_t<R1>, iterator_t<R2>>
      constexpr swap_ranges_result<borrowed_iterator_t<R1>, borrowed_iterator_t<R2>>
        swap_ranges(R1&& r1, R2&& r2);
  }
 
  template<class ForwardIter1, class ForwardIter2>
    constexpr void iter_swap(ForwardIter1 a, ForwardIter2 b);
 
  // 变换
  template<class InputIter, class OutputIter, class UnaryOperation>
    constexpr OutputIter
      transform(InputIter first1, InputIter last1,
                OutputIter result, UnaryOperation op);
  template<class InputIter1, class InputIter2, class OutputIter,
           class BinaryOperation>
    constexpr OutputIter
      transform(InputIter1 first1, InputIter1 last1,
                InputIter2 first2, OutputIter result,
                BinaryOperation binary_op);
  template<class ExecutionPolicy, class ForwardIter1, class ForwardIter2,
           class UnaryOperation>
    ForwardIter2
      transform(ExecutionPolicy&& exec,
                ForwardIter1 first1, ForwardIter1 last1,
                ForwardIter2 result, UnaryOperation op);
  template<class ExecutionPolicy, class ForwardIter1, class ForwardIter2,
           class ForwardIter, class BinaryOperation>
    ForwardIter
      transform(ExecutionPolicy&& exec,
                ForwardIter1 first1, ForwardIter1 last1,
                ForwardIter2 first2, ForwardIter result,
                BinaryOperation binary_op);
 
  namespace ranges {
    template<class I, class O>
      using unary_transform_result = in_out_result<I, O>;
 
    template<input_iterator I, sentinel_for<I> S, weakly_incrementable O,
             copy_constructible F, class Proj = identity>
      requires indirectly_writable<O, indirect_result_t<F&, projected<I, Proj>>>
      constexpr unary_transform_result<I, O>
        transform(I first1, S last1, O result, F op, Proj proj = {});
    template<input_range R, weakly_incrementable O, copy_constructible F,
             class Proj = identity>
      requires indirectly_writable<O, indirect_result_t<F&, projected<iterator_t<R>, Proj>>>
      constexpr unary_transform_result<borrowed_iterator_t<R>, O>
        transform(R&& r, O result, F op, Proj proj = {});
 
    template<class I1, class I2, class O>
      using binary_transform_result = in_in_out_result<I1, I2, O>;
 
    template<input_iterator I1, sentinel_for<I1> S1, input_iterator I2, sentinel_for<I2> S2,
             weakly_incrementable O, copy_constructible F, class Proj1 = identity,
             class Proj2 = identity>
      requires indirectly_writable<O, indirect_result_t<F&, projected<I1, Proj1>,
                                             projected<I2, Proj2>>>
      constexpr binary_transform_result<I1, I2, O>
        transform(I1 first1, S1 last1, I2 first2, S2 last2, O result,
                  F binary_op, Proj1 proj1 = {}, Proj2 proj2 = {});
    template<input_range R1, input_range R2, weakly_incrementable O,
             copy_constructible F, class Proj1 = identity, class Proj2 = identity>
      requires indirectly_writable<O, indirect_result_t<F&, projected<iterator_t<R1>, Proj1>,
                                             projected<iterator_t<R2>, Proj2>>>
      constexpr binary_transform_result<borrowed_iterator_t<R1>, borrowed_iterator_t<R2>, O>
        transform(R1&& r1, R2&& r2, O result,
                  F binary_op, Proj1 proj1 = {}, Proj2 proj2 = {});
  }
 
  // 替换
  template<class ForwardIter, class T>
    constexpr void replace(ForwardIter first, ForwardIter last,
                           const T& old_value, const T& new_value);
  template<class ExecutionPolicy, class ForwardIter, class T>
    void replace(ExecutionPolicy&& exec,
                 ForwardIter first, ForwardIter last,
                 const T& old_value, const T& new_value);
  template<class ForwardIter, class Pred, class T>
    constexpr void replace_if(ForwardIter first, ForwardIter last,
                              Pred pred, const T& new_value);
  template<class ExecutionPolicy, class ForwardIter, class Pred, class T>
    void replace_if(ExecutionPolicy&& exec,
                    ForwardIter first, ForwardIter last,
                    Pred pred, const T& new_value);
 
  namespace ranges {
    template<input_iterator I, sentinel_for<I> S, class T1, class T2, class Proj = identity>
      requires indirectly_writable<I, const T2&> &&
               indirect_binary_predicate<ranges::equal_to, projected<I, Proj>, const T1*>
      constexpr I
        replace(I first, S last, const T1& old_value, const T2& new_value, Proj proj = {});
    template<input_range R, class T1, class T2, class Proj = identity>
      requires indirectly_writable<iterator_t<R>, const T2&> &&
               indirect_binary_predicate<ranges::equal_to,
                                         projected<iterator_t<R>, Proj>, const T1*>
      constexpr borrowed_iterator_t<R>
        replace(R&& r, const T1& old_value, const T2& new_value, Proj proj = {});
    template<input_iterator I, sentinel_for<I> S, class T, class Proj = identity,
             indirect_unary_predicate<projected<I, Proj>> Pred>
      requires indirectly_writable<I, const T&>
      constexpr I replace_if(I first, S last, Pred pred, const T& new_value, Proj proj = {});
    template<input_range R, class T, class Proj = identity,
             indirect_unary_predicate<projected<iterator_t<R>, Proj>> Pred>
      requires indirectly_writable<iterator_t<R>, const T&>
      constexpr borrowed_iterator_t<R>
        replace_if(R&& r, Pred pred, const T& new_value, Proj proj = {});
  }
 
  template<class InputIter, class OutputIter, class T>
    constexpr OutputIter replace_copy(InputIter first, InputIter last,
                                          OutputIter result,
                                          const T& old_value, const T& new_value);
  template<class ExecutionPolicy, class ForwardIter1, class ForwardIter2, class T>
    ForwardIter2 replace_copy(ExecutionPolicy&& exec,
                                  ForwardIter1 first, ForwardIter1 last,
                                  ForwardIter2 result,
                                  const T& old_value, const T& new_value);
  template<class InputIter, class OutputIter, class Pred, class T>
    constexpr OutputIter replace_copy_if(InputIter first, InputIter last,
                                             OutputIter result,
                                             Pred pred, const T& new_value);
  template<class ExecutionPolicy, class ForwardIter1, class ForwardIter2,
           class Pred, class T>
    ForwardIter2 replace_copy_if(ExecutionPolicy&& exec,
                                     ForwardIter1 first, ForwardIter1 last,
                                     ForwardIter2 result,
                                     Pred pred, const T& new_value);
 
  namespace ranges {
    template<class I, class O>
      using replace_copy_result = in_out_result<I, O>;
 
    template<input_iterator I, sentinel_for<I> S, class T1, class T2,
             output_iterator<const T2&> O, class Proj = identity>
      requires indirectly_copyable<I, O> &&
               indirect_binary_predicate<ranges::equal_to, projected<I, Proj>, const T1*>
      constexpr replace_copy_result<I, O>
        replace_copy(I first, S last, O result, const T1& old_value, const T2& new_value,
                     Proj proj = {});
    template<input_range R, class T1, class T2, output_iterator<const T2&> O,
             class Proj = identity>
      requires indirectly_copyable<iterator_t<R>, O> &&
               indirect_binary_predicate<ranges::equal_to,
                                         projected<iterator_t<R>, Proj>, const T1*>
      constexpr replace_copy_result<borrowed_iterator_t<R>, O>
        replace_copy(R&& r, O result, const T1& old_value, const T2& new_value,
                     Proj proj = {});
 
    template<class I, class O>
      using replace_copy_if_result = in_out_result<I, O>;
 
    template<input_iterator I, sentinel_for<I> S, class T, output_iterator<const T&> O,
             class Proj = identity, indirect_unary_predicate<projected<I, Proj>> Pred>
      requires indirectly_copyable<I, O>
      constexpr replace_copy_if_result<I, O>
        replace_copy_if(I first, S last, O result, Pred pred, const T& new_value,
                        Proj proj = {});
    template<input_range R, class T, output_iterator<const T&> O, class Proj = identity,
             indirect_unary_predicate<projected<iterator_t<R>, Proj>> Pred>
      requires indirectly_copyable<iterator_t<R>, O>
      constexpr replace_copy_if_result<borrowed_iterator_t<R>, O>
        replace_copy_if(R&& r, O result, Pred pred, const T& new_value,
                        Proj proj = {});
  }
 
  // 填充
  template<class ForwardIter, class T>
    constexpr void fill(ForwardIter first, ForwardIter last, const T& value);
  template<class ExecutionPolicy, class ForwardIter, class T>
    void fill(ExecutionPolicy&& exec,
              ForwardIter first, ForwardIter last, const T& value);
  template<class OutputIter, class Size, class T>
    constexpr OutputIter fill_n(OutputIter first, Size n, const T& value);
  template<class ExecutionPolicy, class ForwardIter,
           class Size, class T>
    ForwardIter fill_n(ExecutionPolicy&& exec,
                           ForwardIter first, Size n, const T& value);
 
  namespace ranges {
    template<class T, output_iterator<const T&> O, sentinel_for<O> S>
      constexpr O fill(O first, S last, const T& value);
    template<class T, output_range<const T&> R>
      constexpr borrowed_iterator_t<R> fill(R&& r, const T& value);
    template<class T, output_iterator<const T&> O>
      constexpr O fill_n(O first, iter_difference_t<O> n, const T& value);
  }
 
  // 生成
  template<class ForwardIter, class Generator>
    constexpr void generate(ForwardIter first, ForwardIter last,
                            Generator gen);
  template<class ExecutionPolicy, class ForwardIter, class Generator>
    void generate(ExecutionPolicy&& exec,
                  ForwardIter first, ForwardIter last,
                  Generator gen);
  template<class OutputIter, class Size, class Generator>
    constexpr OutputIter generate_n(OutputIter first, Size n, Generator gen);
  template<class ExecutionPolicy, class ForwardIter, class Size, class Generator>
    ForwardIter generate_n(ExecutionPolicy&& exec,
                               ForwardIter first, Size n, Generator gen);
 
  namespace ranges {
    template<input_or_output_iterator O, sentinel_for<O> S, copy_constructible F>
      requires invocable<F&> && indirectly_writable<O, invoke_result_t<F&>>
      constexpr O generate(O first, S last, F gen);
    template<class R, copy_constructible F>
      requires invocable<F&> && output_range<R, invoke_result_t<F&>>
      constexpr borrowed_iterator_t<R> generate(R&& r, F gen);
    template<input_or_output_iterator O, copy_constructible F>
      requires invocable<F&> && indirectly_writable<O, invoke_result_t<F&>>
      constexpr O generate_n(O first, iter_difference_t<O> n, F gen);
  }
 
  // 移除
  template<class ForwardIter, class T>
    constexpr ForwardIter remove(ForwardIter first, ForwardIter last,
                                     const T& value);
  template<class ExecutionPolicy, class ForwardIter, class T>
    ForwardIter remove(ExecutionPolicy&& exec,
                           ForwardIter first, ForwardIter last,
                           const T& value);
  template<class ForwardIter, class Pred>
    constexpr ForwardIter remove_if(ForwardIter first, ForwardIter last,
                                        Pred pred);
  template<class ExecutionPolicy, class ForwardIter, class Pred>
    ForwardIter remove_if(ExecutionPolicy&& exec,
                              ForwardIter first, ForwardIter last,
                              Pred pred);
 
  namespace ranges {
    template<permutable I, sentinel_for<I> S, class T, class Proj = identity>
      requires indirect_binary_predicate<ranges::equal_to, projected<I, Proj>, const T*>
      constexpr subrange<I> remove(I first, S last, const T& value, Proj proj = {});
    template<forward_range R, class T, class Proj = identity>
      requires permutable<iterator_t<R>> &&
               indirect_binary_predicate<ranges::equal_to,
                                         projected<iterator_t<R>, Proj>, const T*>
      constexpr borrowed_subrange_t<R>
        remove(R&& r, const T& value, Proj proj = {});
    template<permutable I, sentinel_for<I> S, class Proj = identity,
             indirect_unary_predicate<projected<I, Proj>> Pred>
      constexpr subrange<I> remove_if(I first, S last, Pred pred, Proj proj = {});
    template<forward_range R, class Proj = identity,
             indirect_unary_predicate<projected<iterator_t<R>, Proj>> Pred>
      requires permutable<iterator_t<R>>
      constexpr borrowed_subrange_t<R>
        remove_if(R&& r, Pred pred, Proj proj = {});
  }
 
  template<class InputIter, class OutputIter, class T>
    constexpr OutputIter
      remove_copy(InputIter first, InputIter last,
                  OutputIter result, const T& value);
  template<class ExecutionPolicy, class ForwardIter1, class ForwardIter2,
           class T>
    ForwardIter2
      remove_copy(ExecutionPolicy&& exec,
                  ForwardIter1 first, ForwardIter1 last,
                  ForwardIter2 result, const T& value);
  template<class InputIter, class OutputIter, class Pred>
    constexpr OutputIter
      remove_copy_if(InputIter first, InputIter last,
                     OutputIter result, Pred pred);
  template<class ExecutionPolicy, class ForwardIter1, class ForwardIter2,
           class Pred>
    ForwardIter2
      remove_copy_if(ExecutionPolicy&& exec,
                     ForwardIter1 first, ForwardIter1 last,
                     ForwardIter2 result, Pred pred);
 
  namespace ranges {
    template<class I, class O>
      using remove_copy_result = in_out_result<I, O>;
 
    template<input_iterator I, sentinel_for<I> S, weakly_incrementable O, class T,
             class Proj = identity>
      requires indirectly_copyable<I, O> &&
               indirect_binary_predicate<ranges::equal_to, projected<I, Proj>, const T*>
      constexpr remove_copy_result<I, O>
        remove_copy(I first, S last, O result, const T& value, Proj proj = {});
    template<input_range R, weakly_incrementable O, class T, class Proj = identity>
      requires indirectly_copyable<iterator_t<R>, O> &&
               indirect_binary_predicate<ranges::equal_to,
                                         projected<iterator_t<R>, Proj>, const T*>
      constexpr remove_copy_result<borrowed_iterator_t<R>, O>
        remove_copy(R&& r, O result, const T& value, Proj proj = {});
 
    template<class I, class O>
      using remove_copy_if_result = in_out_result<I, O>;
 
    template<input_iterator I, sentinel_for<I> S, weakly_incrementable O,
             class Proj = identity, indirect_unary_predicate<projected<I, Proj>> Pred>
      requires indirectly_copyable<I, O>
      constexpr remove_copy_if_result<I, O>
        remove_copy_if(I first, S last, O result, Pred pred, Proj proj = {});
    template<input_range R, weakly_incrementable O, class Proj = identity,
             indirect_unary_predicate<projected<iterator_t<R>, Proj>> Pred>
      requires indirectly_copyable<iterator_t<R>, O>
      constexpr remove_copy_if_result<borrowed_iterator_t<R>, O>
        remove_copy_if(R&& r, O result, Pred pred, Proj proj = {});
  }
 
  // 归一
  template<class ForwardIter>
    constexpr ForwardIter unique(ForwardIter first, ForwardIter last);
  template<class ForwardIter, class BinaryPred>
    constexpr ForwardIter unique(ForwardIter first, ForwardIter last,
                                     BinaryPred pred);
  template<class ExecutionPolicy, class ForwardIter>
    ForwardIter unique(ExecutionPolicy&& exec,
                           ForwardIter first, ForwardIter last);
  template<class ExecutionPolicy, class ForwardIter, class BinaryPred>
    ForwardIter unique(ExecutionPolicy&& exec,
                           ForwardIter first, ForwardIter last,
                           BinaryPred pred);
 
  namespace ranges {
    template<permutable I, sentinel_for<I> S, class Proj = identity,
             indirect_equivalence_relation<projected<I, Proj>> C = ranges::equal_to>
      constexpr subrange<I> unique(I first, S last, C comp = {}, Proj proj = {});
    template<forward_range R, class Proj = identity,
             indirect_equivalence_relation<projected<iterator_t<R>, Proj>> C = ranges::equal_to>
      requires permutable<iterator_t<R>>
      constexpr borrowed_subrange_t<R>
        unique(R&& r, C comp = {}, Proj proj = {});
  }
 
  template<class InputIter, class OutputIter>
    constexpr OutputIter
      unique_copy(InputIter first, InputIter last,
                  OutputIter result);
  template<class InputIter, class OutputIter, class BinaryPred>
    constexpr OutputIter
      unique_copy(InputIter first, InputIter last,
                  OutputIter result, BinaryPred pred);
  template<class ExecutionPolicy, class ForwardIter1, class ForwardIter2>
    ForwardIter2
      unique_copy(ExecutionPolicy&& exec,
                  ForwardIter1 first, ForwardIter1 last,
                  ForwardIter2 result);
  template<class ExecutionPolicy, class ForwardIter1, class ForwardIter2,
           class BinaryPred>
    ForwardIter2
      unique_copy(ExecutionPolicy&& exec,
                  ForwardIter1 first, ForwardIter1 last,
                  ForwardIter2 result, BinaryPred pred);
 
  namespace ranges {
    template<class I, class O>
      using unique_copy_result = in_out_result<I, O>;
 
    template<input_iterator I, sentinel_for<I> S, weakly_incrementable O, class Proj = identity,
             indirect_equivalence_relation<projected<I, Proj>> C = ranges::equal_to>
      requires indirectly_copyable<I, O> &&
               (forward_iterator<I> ||
                (input_iterator<O> && same_as<iter_value_t<I>, iter_value_t<O>>) ||
                indirectly_copyable_storable<I, O>)
      constexpr unique_copy_result<I, O>
        unique_copy(I first, S last, O result, C comp = {}, Proj proj = {});
    template<input_range R, weakly_incrementable O, class Proj = identity,
             indirect_equivalence_relation<projected<iterator_t<R>, Proj>> C = ranges::equal_to>
      requires indirectly_copyable<iterator_t<R>, O> &&
               (forward_iterator<iterator_t<R>> ||
                (input_iterator<O> && same_as<range_value_t<R>, iter_value_t<O>>) ||
                indirectly_copyable_storable<iterator_t<R>, O>)
      constexpr unique_copy_result<borrowed_iterator_t<R>, O>
        unique_copy(R&& r, O result, C comp = {}, Proj proj = {});
  }
 
  // 逆转
  template<class BidirectionalIter>
    constexpr void reverse(BidirectionalIter first, BidirectionalIter last);
  template<class ExecutionPolicy, class BidirectionalIter>
    void reverse(ExecutionPolicy&& exec,
                 BidirectionalIter first, BidirectionalIter last);
 
  namespace ranges {
    template<bidirectional_iterator I, sentinel_for<I> S>
      requires permutable<I>
      constexpr I reverse(I first, S last);
    template<bidirectional_range R>
      requires permutable<iterator_t<R>>
      constexpr borrowed_iterator_t<R> reverse(R&& r);
  }
 
  template<class BidirectionalIter, class OutputIter>
    constexpr OutputIter
      reverse_copy(BidirectionalIter first, BidirectionalIter last,
                   OutputIter result);
  template<class ExecutionPolicy, class BidirectionalIter, class ForwardIter>
    ForwardIter
      reverse_copy(ExecutionPolicy&& exec,
                   BidirectionalIter first, BidirectionalIter last,
                   ForwardIter result);
 
  namespace ranges {
    template<class I, class O>
      using reverse_copy_result = in_out_result<I, O>;
 
    template<bidirectional_iterator I, sentinel_for<I> S, weakly_incrementable O>
      requires indirectly_copyable<I, O>
      constexpr reverse_copy_result<I, O>
        reverse_copy(I first, S last, O result);
    template<bidirectional_range R, weakly_incrementable O>
      requires indirectly_copyable<iterator_t<R>, O>
      constexpr reverse_copy_result<borrowed_iterator_t<R>, O>
        reverse_copy(R&& r, O result);
  }
 
  // 旋转
  template<class ForwardIter>
    constexpr ForwardIter rotate(ForwardIter first,
                                     ForwardIter middle,
                                     ForwardIter last);
  template<class ExecutionPolicy, class ForwardIter>
    ForwardIter rotate(ExecutionPolicy&& exec,
                           ForwardIter first,
                           ForwardIter middle,
                           ForwardIter last);
 
  namespace ranges {
    template<permutable I, sentinel_for<I> S>
      constexpr subrange<I> rotate(I first, I middle, S last);
    template<forward_range R>
      requires permutable<iterator_t<R>>
      constexpr borrowed_subrange_t<R> rotate(R&& r, iterator_t<R> middle);
  }
 
  template<class ForwardIter, class OutputIter>
    constexpr OutputIter
      rotate_copy(ForwardIter first, ForwardIter middle,
                  ForwardIter last, OutputIter result);
  template<class ExecutionPolicy, class ForwardIter1, class ForwardIter2>
    ForwardIter2
      rotate_copy(ExecutionPolicy&& exec,
                  ForwardIter1 first, ForwardIter1 middle,
                  ForwardIter1 last, ForwardIter2 result);
 
  namespace ranges {
    template<class I, class O>
      using rotate_copy_result = in_out_result<I, O>;
 
    template<forward_iterator I, sentinel_for<I> S, weakly_incrementable O>
      requires indirectly_copyable<I, O>
      constexpr rotate_copy_result<I, O>
        rotate_copy(I first, I middle, S last, O result);
    template<forward_range R, weakly_incrementable O>
      requires indirectly_copyable<iterator_t<R>, O>
      constexpr rotate_copy_result<borrowed_iterator_t<R>, O>
        rotate_copy(R&& r, iterator_t<R> middle, O result);
  }
 
  // 采样
  template<class PopulationIter, class SampleIter,
           class Distance, class UniformRandomBitGenerator>
    SampleIter sample(PopulationIter first, PopulationIter last,
                          SampleIter out, Distance n,
                          UniformRandomBitGenerator&& g);
 
  namespace ranges {
    template<input_iterator I, sentinel_for<I> S,
             weakly_incrementable O, class Gen>
      requires (forward_iterator<I> || random_access_iterator<O>) &&
               indirectly_copyable<I, O> &&
               uniform_random_bit_generator<remove_reference_t<Gen>>
      O sample(I first, S last, O out, iter_difference_t<I> n, Gen&& g);
    template<input_range R, weakly_incrementable O, class Gen>
      requires (forward_range<R> || random_access_iterator<O>) &&
               indirectly_copyable<iterator_t<R>, O> &&
               uniform_random_bit_generator<remove_reference_t<Gen>>
      O sample(R&& r, O out, range_difference_t<R> n, Gen&& g);
  }
 
  // 打乱
  template<class RandomAccessIter, class UniformRandomBitGenerator>
    void shuffle(RandomAccessIter first,
                 RandomAccessIter last,
                 UniformRandomBitGenerator&& g);
 
  namespace ranges {
    template<random_access_iterator I, sentinel_for<I> S, class Gen>
      requires permutable<I> &&
               uniform_random_bit_generator<remove_reference_t<Gen>>
      I shuffle(I first, S last, Gen&& g);
    template<random_access_range R, class Gen>
      requires permutable<iterator_t<R>> &&
               uniform_random_bit_generator<remove_reference_t<Gen>>
      borrowed_iterator_t<R> shuffle(R&& r, Gen&& g);
  }
 
  // 迁移
  template<class ForwardIter>
    constexpr ForwardIter
      shift_left(ForwardIter first, ForwardIter last,
                 typename iterator_traits<ForwardIter>::difference_type n);
  template<class ExecutionPolicy, class ForwardIter>
    ForwardIter
      shift_left(ExecutionPolicy&& exec,
                 ForwardIter first, ForwardIter last,
                 typename iterator_traits<ForwardIter>::difference_type n);
  template<class ForwardIter>
    constexpr ForwardIter
      shift_right(ForwardIter first, ForwardIter last,
                  typename iterator_traits<ForwardIter>::difference_type n);
  template<class ExecutionPolicy, class ForwardIter>
    ForwardIter
      shift_right(ExecutionPolicy&& exec,
                  ForwardIter first, ForwardIter last,
                  typename iterator_traits<ForwardIter>::difference_type n);
 
  // 排序与相关操作
  // 排序
  template<class RandomAccessIter>
    constexpr void sort(RandomAccessIter first, RandomAccessIter last);
  template<class RandomAccessIter, class Compare>
    constexpr void sort(RandomAccessIter first, RandomAccessIter last,
                        Compare comp);
  template<class ExecutionPolicy, class RandomAccessIter>
    void sort(ExecutionPolicy&& exec,
              RandomAccessIter first, RandomAccessIter last);
  template<class ExecutionPolicy, class RandomAccessIter, class Compare>
    void sort(ExecutionPolicy&& exec,
              RandomAccessIter first, RandomAccessIter last,
              Compare comp);
 
  namespace ranges {
    template<random_access_iterator I, sentinel_for<I> S, class Comp = ranges::less,
             class Proj = identity>
      requires sortable<I, Comp, Proj>
      constexpr I
        sort(I first, S last, Comp comp = {}, Proj proj = {});
    template<random_access_range R, class Comp = ranges::less, class Proj = identity>
      requires sortable<iterator_t<R>, Comp, Proj>
      constexpr borrowed_iterator_t<R>
        sort(R&& r, Comp comp = {}, Proj proj = {});
  }
 
  template<class RandomAccessIter>
    void stable_sort(RandomAccessIter first, RandomAccessIter last);
  template<class RandomAccessIter, class Compare>
    void stable_sort(RandomAccessIter first, RandomAccessIter last,
                     Compare comp);
  template<class ExecutionPolicy, class RandomAccessIter>
    void stable_sort(ExecutionPolicy&& exec,
                     RandomAccessIter first, RandomAccessIter last);
  template<class ExecutionPolicy, class RandomAccessIter, class Compare>
    void stable_sort(ExecutionPolicy&& exec,
                     RandomAccessIter first, RandomAccessIter last,
                     Compare comp);
 
  namespace ranges {
    template<random_access_iterator I, sentinel_for<I> S, class Comp = ranges::less,
             class Proj = identity>
      requires sortable<I, Comp, Proj>
      I stable_sort(I first, S last, Comp comp = {}, Proj proj = {});
    template<random_access_range R, class Comp = ranges::less, class Proj = identity>
      requires sortable<iterator_t<R>, Comp, Proj>
      borrowed_iterator_t<R>
        stable_sort(R&& r, Comp comp = {}, Proj proj = {});
  }
 
  template<class RandomAccessIter>
    constexpr void partial_sort(RandomAccessIter first, RandomAccessIter middle,
                                RandomAccessIter last);
  template<class RandomAccessIter, class Compare>
    constexpr void partial_sort(RandomAccessIter first, RandomAccessIter middle,
                                RandomAccessIter last, Compare comp);
  template<class ExecutionPolicy, class RandomAccessIter>
    void partial_sort(ExecutionPolicy&& exec,
                      RandomAccessIter first, RandomAccessIter middle,
                      RandomAccessIter last);
  template<class ExecutionPolicy, class RandomAccessIter, class Compare>
    void partial_sort(ExecutionPolicy&& exec,
                      RandomAccessIter first, RandomAccessIter middle,
                      RandomAccessIter last, Compare comp);
 
  namespace ranges {
    template<random_access_iterator I, sentinel_for<I> S, class Comp = ranges::less,
             class Proj = identity>
      requires sortable<I, Comp, Proj>
      constexpr I
        partial_sort(I first, I middle, S last, Comp comp = {}, Proj proj = {});
    template<random_access_range R, class Comp = ranges::less, class Proj = identity>
      requires sortable<iterator_t<R>, Comp, Proj>
      constexpr borrowed_iterator_t<R>
        partial_sort(R&& r, iterator_t<R> middle, Comp comp = {},
                     Proj proj = {});
  }
 
  template<class InputIter, class RandomAccessIter>
    constexpr RandomAccessIter
      partial_sort_copy(InputIter first, InputIter last,
                        RandomAccessIter result_first,
                        RandomAccessIter result_last);
  template<class InputIter, class RandomAccessIter, class Compare>
    constexpr RandomAccessIter
      partial_sort_copy(InputIter first, InputIter last,
                        RandomAccessIter result_first,
                        RandomAccessIter result_last,
                        Compare comp);
  template<class ExecutionPolicy, class ForwardIter, class RandomAccessIter>
    RandomAccessIter
      partial_sort_copy(ExecutionPolicy&& exec,
                        ForwardIter first, ForwardIter last,
                        RandomAccessIter result_first,
                        RandomAccessIter result_last);
  template<class ExecutionPolicy, class ForwardIter, class RandomAccessIter,
           class Compare>
    RandomAccessIter
      partial_sort_copy(ExecutionPolicy&& exec,
                        ForwardIter first, ForwardIter last,
                        RandomAccessIter result_first,
                        RandomAccessIter result_last,
                        Compare comp);
 
  namespace ranges {
    template<class I, class O>
      using partial_sort_copy_result = in_out_result<I, O>;
 
    template<input_iterator I1, sentinel_for<I1> S1,
             random_access_iterator I2, sentinel_for<I2> S2,
             class Comp = ranges::less, class Proj1 = identity, class Proj2 = identity>
      requires indirectly_copyable<I1, I2> && sortable<I2, Comp, Proj2> &&
               indirect_strict_weak_order<Comp, projected<I1, Proj1>, projected<I2, Proj2>>
      constexpr partial_sort_copy_result<I1, I2>
        partial_sort_copy(I1 first, S1 last, I2 result_first, S2 result_last,
                          Comp comp = {}, Proj1 proj1 = {}, Proj2 proj2 = {});
    template<input_range R1, random_access_range R2, class Comp = ranges::less,
             class Proj1 = identity, class Proj2 = identity>
      requires indirectly_copyable<iterator_t<R1>, iterator_t<R2>> &&
               sortable<iterator_t<R2>, Comp, Proj2> &&
               indirect_strict_weak_order<Comp, projected<iterator_t<R1>, Proj1>,
                                          projected<iterator_t<R2>, Proj2>>
      constexpr partial_sort_copy_result<borrowed_iterator_t<R1>, borrowed_iterator_t<R2>>
        partial_sort_copy(R1&& r, R2&& result_r, Comp comp = {},
                          Proj1 proj1 = {}, Proj2 proj2 = {});
  }
 
  template<class ForwardIter>
    constexpr bool is_sorted(ForwardIter first, ForwardIter last);
  template<class ForwardIter, class Compare>
    constexpr bool is_sorted(ForwardIter first, ForwardIter last,
                             Compare comp);
  template<class ExecutionPolicy, class ForwardIter>
    bool is_sorted(ExecutionPolicy&& exec,
                   ForwardIter first, ForwardIter last);
  template<class ExecutionPolicy, class ForwardIter, class Compare>
    bool is_sorted(ExecutionPolicy&& exec,
                   ForwardIter first, ForwardIter last,
                   Compare comp);
 
  namespace ranges {
    template<forward_iterator I, sentinel_for<I> S, class Proj = identity,
             indirect_strict_weak_order<projected<I, Proj>> Comp = ranges::less>
      constexpr bool is_sorted(I first, S last, Comp comp = {}, Proj proj = {});
    template<forward_range R, class Proj = identity,
             indirect_strict_weak_order<projected<iterator_t<R>, Proj>> Comp = ranges::less>
      constexpr bool is_sorted(R&& r, Comp comp = {}, Proj proj = {});
  }
 
  template<class ForwardIter>
    constexpr ForwardIter
      is_sorted_until(ForwardIter first, ForwardIter last);
  template<class ForwardIter, class Compare>
    constexpr ForwardIter
      is_sorted_until(ForwardIter first, ForwardIter last,
                      Compare comp);
  template<class ExecutionPolicy, class ForwardIter>
    ForwardIter
      is_sorted_until(ExecutionPolicy&& exec,
                      ForwardIter first, ForwardIter last);
  template<class ExecutionPolicy, class ForwardIter, class Compare>
    ForwardIter
      is_sorted_until(ExecutionPolicy&& exec,
                      ForwardIter first, ForwardIter last,
                      Compare comp);
 
  namespace ranges {
    template<forward_iterator I, sentinel_for<I> S, class Proj = identity,
             indirect_strict_weak_order<projected<I, Proj>> Comp = ranges::less>
      constexpr I is_sorted_until(I first, S last, Comp comp = {}, Proj proj = {});
    template<forward_range R, class Proj = identity,
             indirect_strict_weak_order<projected<iterator_t<R>, Proj>> Comp = ranges::less>
      constexpr borrowed_iterator_t<R>
        is_sorted_until(R&& r, Comp comp = {}, Proj proj = {});
  }
 
  // 第 N 元素
  template<class RandomAccessIter>
    constexpr void nth_element(RandomAccessIter first, RandomAccessIter nth,
                               RandomAccessIter last);
  template<class RandomAccessIter, class Compare>
    constexpr void nth_element(RandomAccessIter first, RandomAccessIter nth,
                               RandomAccessIter last, Compare comp);
  template<class ExecutionPolicy, class RandomAccessIter>
    void nth_element(ExecutionPolicy&& exec,
                     RandomAccessIter first, RandomAccessIter nth,
                     RandomAccessIter last);
  template<class ExecutionPolicy, class RandomAccessIter, class Compare>
    void nth_element(ExecutionPolicy&& exec,
                     RandomAccessIter first, RandomAccessIter nth,
                     RandomAccessIter last, Compare comp);
 
  namespace ranges {
    template<random_access_iterator I, sentinel_for<I> S, class Comp = ranges::less,
             class Proj = identity>
      requires sortable<I, Comp, Proj>
      constexpr I
        nth_element(I first, I nth, S last, Comp comp = {}, Proj proj = {});
    template<random_access_range R, class Comp = ranges::less, class Proj = identity>
      requires sortable<iterator_t<R>, Comp, Proj>
      constexpr borrowed_iterator_t<R>
        nth_element(R&& r, iterator_t<R> nth, Comp comp = {}, Proj proj = {});
  }
 
  // 二分搜索
  template<class ForwardIter, class T>
    constexpr ForwardIter
      lower_bound(ForwardIter first, ForwardIter last,
                  const T& value);
  template<class ForwardIter, class T, class Compare>
    constexpr ForwardIter
      lower_bound(ForwardIter first, ForwardIter last,
                  const T& value, Compare comp);
 
  namespace ranges {
    template<forward_iterator I, sentinel_for<I> S, class T, class Proj = identity,
             indirect_strict_weak_order<const T*, projected<I, Proj>> Comp = ranges::less>
      constexpr I lower_bound(I first, S last, const T& value, Comp comp = {},
                              Proj proj = {});
    template<forward_range R, class T, class Proj = identity,
             indirect_strict_weak_order<const T*, projected<iterator_t<R>, Proj>> Comp =
               ranges::less>
      constexpr borrowed_iterator_t<R>
        lower_bound(R&& r, const T& value, Comp comp = {}, Proj proj = {});
  }
 
  template<class ForwardIter, class T>
    constexpr ForwardIter
      upper_bound(ForwardIter first, ForwardIter last,
                  const T& value);
  template<class ForwardIter, class T, class Compare>
    constexpr ForwardIter
      upper_bound(ForwardIter first, ForwardIter last,
                  const T& value, Compare comp);
 
  namespace ranges {
    template<forward_iterator I, sentinel_for<I> S, class T, class Proj = identity,
             indirect_strict_weak_order<const T*, projected<I, Proj>> Comp = ranges::less>
      constexpr I upper_bound(I first, S last, const T& value, Comp comp = {}, Proj proj = {});
    template<forward_range R, class T, class Proj = identity,
             indirect_strict_weak_order<const T*, projected<iterator_t<R>, Proj>> Comp =
               ranges::less>
      constexpr borrowed_iterator_t<R>
        upper_bound(R&& r, const T& value, Comp comp = {}, Proj proj = {});
  }
 
  template<class ForwardIter, class T>
    constexpr pair<ForwardIter, ForwardIter>
      equal_range(ForwardIter first, ForwardIter last,
                  const T& value);
  template<class ForwardIter, class T, class Compare>
    constexpr pair<ForwardIter, ForwardIter>
      equal_range(ForwardIter first, ForwardIter last,
                  const T& value, Compare comp);
 
  namespace ranges {
    template<forward_iterator I, sentinel_for<I> S, class T, class Proj = identity,
             indirect_strict_weak_order<const T*, projected<I, Proj>> Comp = ranges::less>
      constexpr subrange<I>
        equal_range(I first, S last, const T& value, Comp comp = {}, Proj proj = {});
    template<forward_range R, class T, class Proj = identity,
             indirect_strict_weak_order<const T*, projected<iterator_t<R>, Proj>> Comp =
               ranges::less>
      constexpr borrowed_subrange_t<R>
        equal_range(R&& r, const T& value, Comp comp = {}, Proj proj = {});
  }
 
  template<class ForwardIter, class T>
    constexpr bool
      binary_search(ForwardIter first, ForwardIter last,
                    const T& value);
  template<class ForwardIter, class T, class Compare>
    constexpr bool
      binary_search(ForwardIter first, ForwardIter last,
                    const T& value, Compare comp);
 
  namespace ranges {
    template<forward_iterator I, sentinel_for<I> S, class T, class Proj = identity,
             indirect_strict_weak_order<const T*, projected<I, Proj>> Comp = ranges::less>
      constexpr bool binary_search(I first, S last, const T& value, Comp comp = {},
                                   Proj proj = {});
    template<forward_range R, class T, class Proj = identity,
             indirect_strict_weak_order<const T*, projected<iterator_t<R>, Proj>> Comp =
               ranges::less>
      constexpr bool binary_search(R&& r, const T& value, Comp comp = {},
                                   Proj proj = {});
  }
 
  // 划分
  template<class InputIter, class Pred>
    constexpr bool is_partitioned(InputIter first, InputIter last, Pred pred);
  template<class ExecutionPolicy, class ForwardIter, class Pred>
    bool is_partitioned(ExecutionPolicy&& exec,
                        ForwardIter first, ForwardIter last, Pred pred);
 
  namespace ranges {
    template<input_iterator I, sentinel_for<I> S, class Proj = identity,
             indirect_unary_predicate<projected<I, Proj>> Pred>
      constexpr bool is_partitioned(I first, S last, Pred pred, Proj proj = {});
    template<input_range R, class Proj = identity,
             indirect_unary_predicate<projected<iterator_t<R>, Proj>> Pred>
      constexpr bool is_partitioned(R&& r, Pred pred, Proj proj = {});
  }
 
  template<class ForwardIter, class Pred>
    constexpr ForwardIter partition(ForwardIter first,
                                        ForwardIter last,
                                        Pred pred);
  template<class ExecutionPolicy, class ForwardIter, class Pred>
    ForwardIter partition(ExecutionPolicy&& exec,
                              ForwardIter first,
                              ForwardIter last,
                              Pred pred);
 
  namespace ranges {
    template<permutable I, sentinel_for<I> S, class Proj = identity,
             indirect_unary_predicate<projected<I, Proj>> Pred>
      constexpr subrange<I>
        partition(I first, S last, Pred pred, Proj proj = {});
    template<forward_range R, class Proj = identity,
             indirect_unary_predicate<projected<iterator_t<R>, Proj>> Pred>
      requires permutable<iterator_t<R>>
      constexpr borrowed_subrange_t<R>
        partition(R&& r, Pred pred, Proj proj = {});
  }
 
  template<class BidirectionalIter, class Pred>
    BidirectionalIter stable_partition(BidirectionalIter first,
                                           BidirectionalIter last,
                                           Pred pred);
  template<class ExecutionPolicy, class BidirectionalIter, class Pred>
    BidirectionalIter stable_partition(ExecutionPolicy&& exec,
                                           BidirectionalIter first,
                                           BidirectionalIter last,
                                           Pred pred);
 
  namespace ranges {
    template<bidirectional_iterator I, sentinel_for<I> S, class Proj = identity,
             indirect_unary_predicate<projected<I, Proj>> Pred>
      requires permutable<I>
      subrange<I> stable_partition(I first, S last, Pred pred, Proj proj = {});
    template<bidirectional_range R, class Proj = identity,
             indirect_unary_predicate<projected<iterator_t<R>, Proj>> Pred>
      requires permutable<iterator_t<R>>
      borrowed_subrange_t<R> stable_partition(R&& r, Pred pred, Proj proj = {});
  }
 
  template<class InputIter, class OutputIter1,
           class OutputIter2, class Pred>
    constexpr pair<OutputIter1, OutputIter2>
      partition_copy(InputIter first, InputIter last,
                     OutputIter1 out_true, OutputIter2 out_false,
                     Pred pred);
  template<class ExecutionPolicy, class ForwardIter, class ForwardIter1,
           class ForwardIter2, class Pred>
    pair<ForwardIter1, ForwardIter2>
      partition_copy(ExecutionPolicy&& exec,
                     ForwardIter first, ForwardIter last,
                     ForwardIter1 out_true, ForwardIter2 out_false,
                     Pred pred);
 
  namespace ranges {
    template<class I, class O1, class O2>
      using partition_copy_result = in_out_out_result<I, O1, O2>;
 
    template<input_iterator I, sentinel_for<I> S,
             weakly_incrementable O1, weakly_incrementable O2,
             class Proj = identity, indirect_unary_predicate<projected<I, Proj>> Pred>
      requires indirectly_copyable<I, O1> && indirectly_copyable<I, O2>
      constexpr partition_copy_result<I, O1, O2>
        partition_copy(I first, S last, O1 out_true, O2 out_false, Pred pred,
                       Proj proj = {});
    template<input_range R, weakly_incrementable O1, weakly_incrementable O2,
             class Proj = identity,
             indirect_unary_predicate<projected<iterator_t<R>, Proj>> Pred>
      requires indirectly_copyable<iterator_t<R>, O1> &&
               indirectly_copyable<iterator_t<R>, O2>
      constexpr partition_copy_result<borrowed_iterator_t<R>, O1, O2>
        partition_copy(R&& r, O1 out_true, O2 out_false, Pred pred, Proj proj = {});
  }
 
  template<class ForwardIter, class Pred>
    constexpr ForwardIter
      partition_point(ForwardIter first, ForwardIter last,
                      Pred pred);
 
  namespace ranges {
    template<forward_iterator I, sentinel_for<I> S, class Proj = identity,
             indirect_unary_predicate<projected<I, Proj>> Pred>
      constexpr I partition_point(I first, S last, Pred pred, Proj proj = {});
    template<forward_range R, class Proj = identity,
             indirect_unary_predicate<projected<iterator_t<R>, Proj>> Pred>
      constexpr borrowed_iterator_t<R>
        partition_point(R&& r, Pred pred, Proj proj = {});
  }
 
  // 归并
  template<class InputIter1, class InputIter2, class OutputIter>
    constexpr OutputIter
      merge(InputIter1 first1, InputIter1 last1,
            InputIter2 first2, InputIter2 last2,
            OutputIter result);
  template<class InputIter1, class InputIter2, class OutputIter,
           class Compare>
    constexpr OutputIter
      merge(InputIter1 first1, InputIter1 last1,
            InputIter2 first2, InputIter2 last2,
            OutputIter result, Compare comp);
  template<class ExecutionPolicy, class ForwardIter1, class ForwardIter2,
           class ForwardIter>
    ForwardIter
      merge(ExecutionPolicy&& exec,
            ForwardIter1 first1, ForwardIter1 last1,
            ForwardIter2 first2, ForwardIter2 last2,
            ForwardIter result);
  template<class ExecutionPolicy, class ForwardIter1, class ForwardIter2,
           class ForwardIter, class Compare>
    ForwardIter
      merge(ExecutionPolicy&& exec,
            ForwardIter1 first1, ForwardIter1 last1,
            ForwardIter2 first2, ForwardIter2 last2,
            ForwardIter result, Compare comp);
 
  namespace ranges {
    template<class I1, class I2, class O>
      using merge_result = in_in_out_result<I1, I2, O>;
 
    template<input_iterator I1, sentinel_for<I1> S1, input_iterator I2, sentinel_for<I2> S2,
             weakly_incrementable O, class Comp = ranges::less, class Proj1 = identity,
             class Proj2 = identity>
      requires mergeable<I1, I2, O, Comp, Proj1, Proj2>
      constexpr merge_result<I1, I2, O>
        merge(I1 first1, S1 last1, I2 first2, S2 last2, O result,
              Comp comp = {}, Proj1 proj1 = {}, Proj2 proj2 = {});
    template<input_range R1, input_range R2, weakly_incrementable O, class Comp = ranges::less,
             class Proj1 = identity, class Proj2 = identity>
      requires mergeable<iterator_t<R1>, iterator_t<R2>, O, Comp, Proj1, Proj2>
      constexpr merge_result<borrowed_iterator_t<R1>, borrowed_iterator_t<R2>, O>
        merge(R1&& r1, R2&& r2, O result,
              Comp comp = {}, Proj1 proj1 = {}, Proj2 proj2 = {});
  }
 
  template<class BidirectionalIter>
    void inplace_merge(BidirectionalIter first,
                       BidirectionalIter middle,
                       BidirectionalIter last);
  template<class BidirectionalIter, class Compare>
    void inplace_merge(BidirectionalIter first,
                       BidirectionalIter middle,
                       BidirectionalIter last, Compare comp);
  template<class ExecutionPolicy, class BidirectionalIter>
    void inplace_merge(ExecutionPolicy&& exec,
                       BidirectionalIter first,
                       BidirectionalIter middle,
                       BidirectionalIter last);
  template<class ExecutionPolicy, class BidirectionalIter, class Compare>
    void inplace_merge(ExecutionPolicy&& exec,
                       BidirectionalIter first,
                       BidirectionalIter middle,
                       BidirectionalIter last, Compare comp);
 
  namespace ranges {
    template<bidirectional_iterator I, sentinel_for<I> S, class Comp = ranges::less,
             class Proj = identity>
      requires sortable<I, Comp, Proj>
      I inplace_merge(I first, I middle, S last, Comp comp = {}, Proj proj = {});
    template<bidirectional_range R, class Comp = ranges::less, class Proj = identity>
      requires sortable<iterator_t<R>, Comp, Proj>
      borrowed_iterator_t<R>
        inplace_merge(R&& r, iterator_t<R> middle, Comp comp = {},
                      Proj proj = {});
  }
 
  // 集合操作
  template<class InputIter1, class InputIter2>
    constexpr bool includes(InputIter1 first1, InputIter1 last1,
                            InputIter2 first2, InputIter2 last2);
  template<class InputIter1, class InputIter2, class Compare>
    constexpr bool includes(InputIter1 first1, InputIter1 last1,
                            InputIter2 first2, InputIter2 last2,
                            Compare comp);
  template<class ExecutionPolicy, class ForwardIter1, class ForwardIter2>
    bool includes(ExecutionPolicy&& exec,
                  ForwardIter1 first1, ForwardIter1 last1,
                  ForwardIter2 first2, ForwardIter2 last2);
  template<class ExecutionPolicy, class ForwardIter1, class ForwardIter2,
           class Compare>
    bool includes(ExecutionPolicy&& exec,
                  ForwardIter1 first1, ForwardIter1 last1,
                  ForwardIter2 first2, ForwardIter2 last2,
                  Compare comp);
 
  namespace ranges {
    template<input_iterator I1, sentinel_for<I1> S1, input_iterator I2, sentinel_for<I2> S2,
             class Proj1 = identity, class Proj2 = identity,
             indirect_strict_weak_order<projected<I1, Proj1>, projected<I2, Proj2>> Comp =
               ranges::less>
      constexpr bool includes(I1 first1, S1 last1, I2 first2, S2 last2, Comp comp = {},
                              Proj1 proj1 = {}, Proj2 proj2 = {});
    template<input_range R1, input_range R2, class Proj1 = identity,
             class Proj2 = identity,
             indirect_strict_weak_order<projected<iterator_t<R1>, Proj1>,
                                        projected<iterator_t<R2>, Proj2>> Comp = ranges::less>
      constexpr bool includes(R1&& r1, R2&& r2, Comp comp = {},
                              Proj1 proj1 = {}, Proj2 proj2 = {});
  }
 
  template<class InputIter1, class InputIter2, class OutputIter>
    constexpr OutputIter
      set_union(InputIter1 first1, InputIter1 last1,
                InputIter2 first2, InputIter2 last2,
                OutputIter result);
  template<class InputIter1, class InputIter2, class OutputIter, class Compare>
    constexpr OutputIter
                set_union(InputIter1 first1, InputIter1 last1,
                InputIter2 first2, InputIter2 last2,
                OutputIter result, Compare comp);
  template<class ExecutionPolicy, class ForwardIter1, class ForwardIter2,
           class ForwardIter>
    ForwardIter
      set_union(ExecutionPolicy&& exec,
                ForwardIter1 first1, ForwardIter1 last1,
                ForwardIter2 first2, ForwardIter2 last2,
                ForwardIter result);
  template<class ExecutionPolicy, class ForwardIter1, class ForwardIter2,
           class ForwardIter, class Compare>
    ForwardIter
      set_union(ExecutionPolicy&& exec,
                ForwardIter1 first1, ForwardIter1 last1,
                ForwardIter2 first2, ForwardIter2 last2,
                ForwardIter result, Compare comp);
 
  namespace ranges {
    template<class I1, class I2, class O>
      using set_union_result = in_in_out_result<I1, I2, O>;
 
    template<input_iterator I1, sentinel_for<I1> S1, input_iterator I2, sentinel_for<I2> S2,
             weakly_incrementable O, class Comp = ranges::less,
             class Proj1 = identity, class Proj2 = identity>
      requires mergeable<I1, I2, O, Comp, Proj1, Proj2>
      constexpr set_union_result<I1, I2, O>
        set_union(I1 first1, S1 last1, I2 first2, S2 last2, O result, Comp comp = {},
                  Proj1 proj1 = {}, Proj2 proj2 = {});
    template<input_range R1, input_range R2, weakly_incrementable O,
             class Comp = ranges::less, class Proj1 = identity, class Proj2 = identity>
      requires mergeable<iterator_t<R1>, iterator_t<R2>, O, Comp, Proj1, Proj2>
      constexpr set_union_result<borrowed_iterator_t<R1>, borrowed_iterator_t<R2>, O>
        set_union(R1&& r1, R2&& r2, O result, Comp comp = {},
                  Proj1 proj1 = {}, Proj2 proj2 = {});
  }
 
  template<class InputIter1, class InputIter2, class OutputIter>
    constexpr OutputIter
      set_intersection(InputIter1 first1, InputIter1 last1,
                       InputIter2 first2, InputIter2 last2,
                       OutputIter result);
  template<class InputIter1, class InputIter2, class OutputIter, class Compare>
    constexpr OutputIter
      set_intersection(InputIter1 first1, InputIter1 last1,
                       InputIter2 first2, InputIter2 last2,
                       OutputIter result, Compare comp);
  template<class ExecutionPolicy, class ForwardIter1, class ForwardIter2,
           class ForwardIter>
    ForwardIter
      set_intersection(ExecutionPolicy&& exec,
                       ForwardIter1 first1, ForwardIter1 last1,
                       ForwardIter2 first2, ForwardIter2 last2,
                       ForwardIter result);
  template<class ExecutionPolicy, class ForwardIter1, class ForwardIter2,
           class ForwardIter, class Compare>
    ForwardIter
      set_intersection(ExecutionPolicy&& exec,
                       ForwardIter1 first1, ForwardIter1 last1,
                       ForwardIter2 first2, ForwardIter2 last2,
                       ForwardIter result, Compare comp);
 
  namespace ranges {
    template<class I1, class I2, class O>
      using set_intersection_result = in_in_out_result<I1, I2, O>;
 
    template<input_iterator I1, sentinel_for<I1> S1, input_iterator I2, sentinel_for<I2> S2,
             weakly_incrementable O, class Comp = ranges::less,
             class Proj1 = identity, class Proj2 = identity>
      requires mergeable<I1, I2, O, Comp, Proj1, Proj2>
      constexpr set_intersection_result<I1, I2, O>
        set_intersection(I1 first1, S1 last1, I2 first2, S2 last2, O result,
                         Comp comp = {}, Proj1 proj1 = {}, Proj2 proj2 = {});
    template<input_range R1, input_range R2, weakly_incrementable O,
             class Comp = ranges::less, class Proj1 = identity, class Proj2 = identity>
      requires mergeable<iterator_t<R1>, iterator_t<R2>, O, Comp, Proj1, Proj2>
      constexpr set_intersection_result<borrowed_iterator_t<R1>, borrowed_iterator_t<R2>, O>
        set_intersection(R1&& r1, R2&& r2, O result,
                         Comp comp = {}, Proj1 proj1 = {}, Proj2 proj2 = {});
  }
 
  template<class InputIter1, class InputIter2, class OutputIter>
    constexpr OutputIter
      set_difference(InputIter1 first1, InputIter1 last1,
                     InputIter2 first2, InputIter2 last2,
                     OutputIter result);
  template<class InputIter1, class InputIter2, class OutputIter, class Compare>
    constexpr OutputIter
      set_difference(InputIter1 first1, InputIter1 last1,
                     InputIter2 first2, InputIter2 last2,
                     OutputIter result, Compare comp);
  template<class ExecutionPolicy, class ForwardIter1, class ForwardIter2,
           class ForwardIter>
    ForwardIter
      set_difference(ExecutionPolicy&& exec,
                     ForwardIter1 first1, ForwardIter1 last1,
                     ForwardIter2 first2, ForwardIter2 last2,
                     ForwardIter result);
  template<class ExecutionPolicy, class ForwardIter1, class ForwardIter2,
           class ForwardIter, class Compare>
    ForwardIter
      set_difference(ExecutionPolicy&& exec,
                     ForwardIter1 first1, ForwardIter1 last1,
                     ForwardIter2 first2, ForwardIter2 last2,
                     ForwardIter result, Compare comp);
 
  namespace ranges {
    template<class I, class O>
      using set_difference_result = in_out_result<I, O>;
 
    template<input_iterator I1, sentinel_for<I1> S1, input_iterator I2, sentinel_for<I2> S2,
             weakly_incrementable O, class Comp = ranges::less,
             class Proj1 = identity, class Proj2 = identity>
      requires mergeable<I1, I2, O, Comp, Proj1, Proj2>
      constexpr set_difference_result<I1, O>
        set_difference(I1 first1, S1 last1, I2 first2, S2 last2, O result,
                       Comp comp = {}, Proj1 proj1 = {}, Proj2 proj2 = {});
    template<input_range R1, input_range R2, weakly_incrementable O,
             class Comp = ranges::less, class Proj1 = identity, class Proj2 = identity>
      requires mergeable<iterator_t<R1>, iterator_t<R2>, O, Comp, Proj1, Proj2>
      constexpr set_difference_result<borrowed_iterator_t<R1>, O>
        set_difference(R1&& r1, R2&& r2, O result,
                       Comp comp = {}, Proj1 proj1 = {}, Proj2 proj2 = {});
  }
 
  template<class InputIter1, class InputIter2, class OutputIter>
    constexpr OutputIter
      set_symmetric_difference(InputIter1 first1, InputIter1 last1,
                               InputIter2 first2, InputIter2 last2,
                               OutputIter result);
  template<class InputIter1, class InputIter2, class OutputIter, class Compare>
    constexpr OutputIter
      set_symmetric_difference(InputIter1 first1, InputIter1 last1,
                               InputIter2 first2, InputIter2 last2,
                               OutputIter result, Compare comp);
  template<class ExecutionPolicy, class ForwardIter1, class ForwardIter2,
           class ForwardIter>
    ForwardIter
      set_symmetric_difference(ExecutionPolicy&& exec,
                               ForwardIter1 first1, ForwardIter1 last1,
                               ForwardIter2 first2, ForwardIter2 last2,
                               ForwardIter result);
  template<class ExecutionPolicy, class ForwardIter1, class ForwardIter2,
           class ForwardIter, class Compare>
    ForwardIter
      set_symmetric_difference(ExecutionPolicy&& exec,
                               ForwardIter1 first1, ForwardIter1 last1,
                               ForwardIter2 first2, ForwardIter2 last2,
                               ForwardIter result, Compare comp);
 
  namespace ranges {
    template<class I1, class I2, class O>
      using set_symmetric_difference_result = in_in_out_result<I1, I2, O>;
 
    template<input_iterator I1, sentinel_for<I1> S1, input_iterator I2, sentinel_for<I2> S2,
             weakly_incrementable O, class Comp = ranges::less,
             class Proj1 = identity, class Proj2 = identity>
      requires mergeable<I1, I2, O, Comp, Proj1, Proj2>
      constexpr set_symmetric_difference_result<I1, I2, O>
        set_symmetric_difference(I1 first1, S1 last1, I2 first2, S2 last2, O result,
                                 Comp comp = {}, Proj1 proj1 = {},
                                 Proj2 proj2 = {});
    template<input_range R1, input_range R2, weakly_incrementable O,
             class Comp = ranges::less, class Proj1 = identity, class Proj2 = identity>
      requires mergeable<iterator_t<R1>, iterator_t<R2>, O, Comp, Proj1, Proj2>
      constexpr set_symmetric_difference_result<borrowed_iterator_t<R1>,
                                                borrowed_iterator_t<R2>, O>
        set_symmetric_difference(R1&& r1, R2&& r2, O result, Comp comp = {},
                                 Proj1 proj1 = {}, Proj2 proj2 = {});
  }
 
  // 堆操作
  template<class RandomAccessIter>
    constexpr void push_heap(RandomAccessIter first, RandomAccessIter last);
  template<class RandomAccessIter, class Compare>
    constexpr void push_heap(RandomAccessIter first, RandomAccessIter last,
                             Compare comp);
 
  namespace ranges {
    template<random_access_iterator I, sentinel_for<I> S, class Comp = ranges::less,
             class Proj = identity>
      requires sortable<I, Comp, Proj>
      constexpr I
        push_heap(I first, S last, Comp comp = {}, Proj proj = {});
    template<random_access_range R, class Comp = ranges::less, class Proj = identity>
      requires sortable<iterator_t<R>, Comp, Proj>
      constexpr borrowed_iterator_t<R>
        push_heap(R&& r, Comp comp = {}, Proj proj = {});
  }
 
  template<class RandomAccessIter>
    constexpr void pop_heap(RandomAccessIter first, RandomAccessIter last);
  template<class RandomAccessIter, class Compare>
    constexpr void pop_heap(RandomAccessIter first, RandomAccessIter last,
                            Compare comp);
 
  namespace ranges {
    template<random_access_iterator I, sentinel_for<I> S, class Comp = ranges::less,
             class Proj = identity>
      requires sortable<I, Comp, Proj>
      constexpr I
        pop_heap(I first, S last, Comp comp = {}, Proj proj = {});
    template<random_access_range R, class Comp = ranges::less, class Proj = identity>
      requires sortable<iterator_t<R>, Comp, Proj>
      constexpr borrowed_iterator_t<R>
        pop_heap(R&& r, Comp comp = {}, Proj proj = {});
  }
 
  template<class RandomAccessIter>
    constexpr void make_heap(RandomAccessIter first, RandomAccessIter last);
  template<class RandomAccessIter, class Compare>
    constexpr void make_heap(RandomAccessIter first, RandomAccessIter last,
                             Compare comp);
 
  namespace ranges {
    template<random_access_iterator I, sentinel_for<I> S, class Comp = ranges::less,
             class Proj = identity>
      requires sortable<I, Comp, Proj>
      constexpr I
        make_heap(I first, S last, Comp comp = {}, Proj proj = {});
    template<random_access_range R, class Comp = ranges::less, class Proj = identity>
      requires sortable<iterator_t<R>, Comp, Proj>
      constexpr borrowed_iterator_t<R>
        make_heap(R&& r, Comp comp = {}, Proj proj = {});
  }
 
  template<class RandomAccessIter>
    constexpr void sort_heap(RandomAccessIter first, RandomAccessIter last);
  template<class RandomAccessIter, class Compare>
    constexpr void sort_heap(RandomAccessIter first, RandomAccessIter last,
                             Compare comp);
 
  namespace ranges {
    template<random_access_iterator I, sentinel_for<I> S, class Comp = ranges::less,
             class Proj = identity>
      requires sortable<I, Comp, Proj>
      constexpr I
        sort_heap(I first, S last, Comp comp = {}, Proj proj = {});
    template<random_access_range R, class Comp = ranges::less, class Proj = identity>
      requires sortable<iterator_t<R>, Comp, Proj>
      constexpr borrowed_iterator_t<R>
        sort_heap(R&& r, Comp comp = {}, Proj proj = {});
  }
 
  template<class RandomAccessIter>
    constexpr bool is_heap(RandomAccessIter first, RandomAccessIter last);
  template<class RandomAccessIter, class Compare>
    constexpr bool is_heap(RandomAccessIter first, RandomAccessIter last,
                           Compare comp);
  template<class ExecutionPolicy, class RandomAccessIter>
    bool is_heap(ExecutionPolicy&& exec,
                 RandomAccessIter first, RandomAccessIter last);
  template<class ExecutionPolicy, class RandomAccessIter, class Compare>
    bool is_heap(ExecutionPolicy&& exec,
                 RandomAccessIter first, RandomAccessIter last,
                 Compare comp);
 
  namespace ranges {
    template<random_access_iterator I, sentinel_for<I> S, class Proj = identity,
             indirect_strict_weak_order<projected<I, Proj>> Comp = ranges::less>
      constexpr bool is_heap(I first, S last, Comp comp = {}, Proj proj = {});
    template<random_access_range R, class Proj = identity,
             indirect_strict_weak_order<projected<iterator_t<R>, Proj>> Comp = ranges::less>
      constexpr bool is_heap(R&& r, Comp comp = {}, Proj proj = {});
  }
 
  template<class RandomAccessIter>
    constexpr RandomAccessIter
      is_heap_until(RandomAccessIter first, RandomAccessIter last);
  template<class RandomAccessIter, class Compare>
    constexpr RandomAccessIter
      is_heap_until(RandomAccessIter first, RandomAccessIter last,
                    Compare comp);
  template<class ExecutionPolicy, class RandomAccessIter>
    RandomAccessIter
      is_heap_until(ExecutionPolicy&& exec,
                    RandomAccessIter first, RandomAccessIter last);
  template<class ExecutionPolicy, class RandomAccessIter, class Compare>
    RandomAccessIter
      is_heap_until(ExecutionPolicy&& exec,
                    RandomAccessIter first, RandomAccessIter last,
                    Compare comp);
 
  namespace ranges {
    template<random_access_iterator I, sentinel_for<I> S, class Proj = identity,
             indirect_strict_weak_order<projected<I, Proj>> Comp = ranges::less>
      constexpr I is_heap_until(I first, S last, Comp comp = {}, Proj proj = {});
    template<random_access_range R, class Proj = identity,
             indirect_strict_weak_order<projected<iterator_t<R>, Proj>> Comp = ranges::less>
      constexpr borrowed_iterator_t<R>
        is_heap_until(R&& r, Comp comp = {}, Proj proj = {});
  }
 
  // 最小与最大
  template<class T> constexpr const T& min(const T& a, const T& b);
  template<class T, class Compare>
    constexpr const T& min(const T& a, const T& b, Compare comp);
  template<class T>
    constexpr T min(initializer_list<T> t);
  template<class T, class Compare>
    constexpr T min(initializer_list<T> t, Compare comp);
 
  namespace ranges {
    template<class T, class Proj = identity,
             indirect_strict_weak_order<projected<const T*, Proj>> Comp = ranges::less>
      constexpr const T& min(const T& a, const T& b, Comp comp = {}, Proj proj = {});
    template<copyable T, class Proj = identity,
             indirect_strict_weak_order<projected<const T*, Proj>> Comp = ranges::less>
      constexpr T min(initializer_list<T> r, Comp comp = {}, Proj proj = {});
    template<input_range R, class Proj = identity,
             indirect_strict_weak_order<projected<iterator_t<R>, Proj>> Comp = ranges::less>
      requires indirectly_copyable_storable<iterator_t<R>, range_value_t<R>*>
      constexpr range_value_t<R>
        min(R&& r, Comp comp = {}, Proj proj = {});
  }
 
  template<class T> constexpr const T& max(const T& a, const T& b);
  template<class T, class Compare>
    constexpr const T& max(const T& a, const T& b, Compare comp);
  template<class T>
    constexpr T max(initializer_list<T> t);
  template<class T, class Compare>
    constexpr T max(initializer_list<T> t, Compare comp);
 
  namespace ranges {
    template<class T, class Proj = identity,
             indirect_strict_weak_order<projected<const T*, Proj>> Comp = ranges::less>
      constexpr const T& max(const T& a, const T& b, Comp comp = {}, Proj proj = {});
    template<copyable T, class Proj = identity,
             indirect_strict_weak_order<projected<const T*, Proj>> Comp = ranges::less>
      constexpr T max(initializer_list<T> r, Comp comp = {}, Proj proj = {});
    template<input_range R, class Proj = identity,
             indirect_strict_weak_order<projected<iterator_t<R>, Proj>> Comp = ranges::less>
      requires indirectly_copyable_storable<iterator_t<R>, range_value_t<R>*>
      constexpr range_value_t<R>
        max(R&& r, Comp comp = {}, Proj proj = {});
  }
 
  template<class T> constexpr pair<const T&, const T&> minmax(const T& a, const T& b);
  template<class T, class Compare>
    constexpr pair<const T&, const T&> minmax(const T& a, const T& b, Compare comp);
  template<class T>
    constexpr pair<T, T> minmax(initializer_list<T> t);
  template<class T, class Compare>
    constexpr pair<T, T> minmax(initializer_list<T> t, Compare comp);
 
  namespace ranges {
    template<class T>
      using minmax_result = min_max_result<T>;
 
    template<class T, class Proj = identity,
             indirect_strict_weak_order<projected<const T*, Proj>> Comp = ranges::less>
      constexpr minmax_result<const T&>
        minmax(const T& a, const T& b, Comp comp = {}, Proj proj = {});
    template<copyable T, class Proj = identity,
             indirect_strict_weak_order<projected<const T*, Proj>> Comp = ranges::less>
      constexpr minmax_result<T>
        minmax(initializer_list<T> r, Comp comp = {}, Proj proj = {});
    template<input_range R, class Proj = identity,
             indirect_strict_weak_order<projected<iterator_t<R>, Proj>> Comp = ranges::less>
      requires indirectly_copyable_storable<iterator_t<R>, range_value_t<R>*>
      constexpr minmax_result<range_value_t<R>>
        minmax(R&& r, Comp comp = {}, Proj proj = {});
  }
 
  template<class ForwardIter>
    constexpr ForwardIter min_element(ForwardIter first, ForwardIter last);
  template<class ForwardIter, class Compare>
    constexpr ForwardIter min_element(ForwardIter first, ForwardIter last,
                                          Compare comp);
  template<class ExecutionPolicy, class ForwardIter>
    ForwardIter min_element(ExecutionPolicy&& exec,
                                ForwardIter first, ForwardIter last);
  template<class ExecutionPolicy, class ForwardIter, class Compare>
    ForwardIter min_element(ExecutionPolicy&& exec,
                                ForwardIter first, ForwardIter last,
                                Compare comp);
 
  namespace ranges {
    template<forward_iterator I, sentinel_for<I> S, class Proj = identity,
             indirect_strict_weak_order<projected<I, Proj>> Comp = ranges::less>
      constexpr I min_element(I first, S last, Comp comp = {}, Proj proj = {});
    template<forward_range R, class Proj = identity,
             indirect_strict_weak_order<projected<iterator_t<R>, Proj>> Comp = ranges::less>
      constexpr borrowed_iterator_t<R>
        min_element(R&& r, Comp comp = {}, Proj proj = {});
  }
 
  template<class ForwardIter>
    constexpr ForwardIter max_element(ForwardIter first, ForwardIter last);
  template<class ForwardIter, class Compare>
    constexpr ForwardIter max_element(ForwardIter first, ForwardIter last,
                                          Compare comp);
  template<class ExecutionPolicy, class ForwardIter>
    ForwardIter max_element(ExecutionPolicy&& exec,
                                ForwardIter first, ForwardIter last);
  template<class ExecutionPolicy, class ForwardIter, class Compare>
    ForwardIter max_element(ExecutionPolicy&& exec,
                                ForwardIter first, ForwardIter last,
                                Compare comp);
 
 namespace ranges {
    template<forward_iterator I, sentinel_for<I> S, class Proj = identity,
             indirect_strict_weak_order<projected<I, Proj>> Comp = ranges::less>
      constexpr I max_element(I first, S last, Comp comp = {}, Proj proj = {});
    template<forward_range R, class Proj = identity,
             indirect_strict_weak_order<projected<iterator_t<R>, Proj>> Comp = ranges::less>
      constexpr borrowed_iterator_t<R>
        max_element(R&& r, Comp comp = {}, Proj proj = {});
  }
 
  template<class ForwardIter>
    constexpr pair<ForwardIter, ForwardIter>
      minmax_element(ForwardIter first, ForwardIter last);
  template<class ForwardIter, class Compare>
    constexpr pair<ForwardIter, ForwardIter>
      minmax_element(ForwardIter first, ForwardIter last, Compare comp);
  template<class ExecutionPolicy, class ForwardIter>
    pair<ForwardIter, ForwardIter>
      minmax_element(ExecutionPolicy&& exec,
                     ForwardIter first, ForwardIter last);
  template<class ExecutionPolicy, class ForwardIter, class Compare>
    pair<ForwardIter, ForwardIter>
      minmax_element(ExecutionPolicy&& exec,
                     ForwardIter first, ForwardIter last, Compare comp);
 
  namespace ranges {
    template<class I>
      using minmax_element_result = min_max_result<I>;
 
    template<forward_iterator I, sentinel_for<I> S, class Proj = identity,
             indirect_strict_weak_order<projected<I, Proj>> Comp = ranges::less>
      constexpr minmax_element_result<I>
        minmax_element(I first, S last, Comp comp = {}, Proj proj = {});
    template<forward_range R, class Proj = identity,
             indirect_strict_weak_order<projected<iterator_t<R>, Proj>> Comp = ranges::less>
      constexpr minmax_element_result<borrowed_iterator_t<R>>
        minmax_element(R&& r, Comp comp = {}, Proj proj = {});
  }
 
  // 有界值
  template<class T>
    constexpr const T& clamp(const T& v, const T& lo, const T& hi);
  template<class T, class Compare>
    constexpr const T& clamp(const T& v, const T& lo, const T& hi, Compare comp);
 
  namespace ranges {
    template<class T, class Proj = identity,
             indirect_strict_weak_order<projected<const T*, Proj>> Comp = ranges::less>
      constexpr const T&
        clamp(const T& v, const T& lo, const T& hi, Comp comp = {}, Proj proj = {});
  }
 
  // 字典序比较
  template<class InputIter1, class InputIter2>
    constexpr bool
      lexicographical_compare(InputIter1 first1, InputIter1 last1,
                              InputIter2 first2, InputIter2 last2);
  template<class InputIter1, class InputIter2, class Compare>
    constexpr bool
      lexicographical_compare(InputIter1 first1, InputIter1 last1,
                              InputIter2 first2, InputIter2 last2,
                              Compare comp);
  template<class ExecutionPolicy, class ForwardIter1, class ForwardIter2>
    bool
      lexicographical_compare(ExecutionPolicy&& exec,
                              ForwardIter1 first1, ForwardIter1 last1,
                              ForwardIter2 first2, ForwardIter2 last2);
  template<class ExecutionPolicy, class ForwardIter1, class ForwardIter2,
           class Compare>
    bool
      lexicographical_compare(ExecutionPolicy&& exec,
                              ForwardIter1 first1, ForwardIter1 last1,
                              ForwardIter2 first2, ForwardIter2 last2,
                              Compare comp);
 
  namespace ranges {
    template<input_iterator I1, sentinel_for<I1> S1, input_iterator I2, sentinel_for<I2> S2,
             class Proj1 = identity, class Proj2 = identity,
             indirect_strict_weak_order<projected<I1, Proj1>, projected<I2, Proj2>> Comp =
               ranges::less>
      constexpr bool
        lexicographical_compare(I1 first1, S1 last1, I2 first2, S2 last2,
                                Comp comp = {}, Proj1 proj1 = {}, Proj2 proj2 = {});
    template<input_range R1, input_range R2, class Proj1 = identity,
             class Proj2 = identity,
             indirect_strict_weak_order<projected<iterator_t<R1>, Proj1>,
                                        projected<iterator_t<R2>, Proj2>> Comp = ranges::less>
      constexpr bool
        lexicographical_compare(R1&& r1, R2&& r2, Comp comp = {},
                                Proj1 proj1 = {}, Proj2 proj2 = {});
  }
 
  // 三路比较算法
  template<class InputIter1, class InputIter2, class Cmp>
    constexpr auto
      lexicographical_compare_three_way(InputIter1 b1, InputIter1 e1,
                                        InputIter2 b2, InputIter2 e2,
                                        Cmp comp)
        -> decltype(comp(*b1, *b2));
  template<class InputIter1, class InputIter2>
    constexpr auto
      lexicographical_compare_three_way(InputIter1 b1, InputIter1 e1,
                                        InputIter2 b2, InputIter2 e2);
 
  // 排列
  template<class BidirectionalIter>
    constexpr bool next_permutation(BidirectionalIter first,
                                    BidirectionalIter last);
  template<class BidirectionalIter, class Compare>
    constexpr bool next_permutation(BidirectionalIter first,
                                    BidirectionalIter last, Compare comp);
 
  namespace ranges {
    template<class I>
      using next_permutation_result = in_found_result<I>;
 
    template<bidirectional_iterator I, sentinel_for<I> S, class Comp = ranges::less,
             class Proj = identity>
      requires sortable<I, Comp, Proj>
      constexpr next_permutation_result<I>
        next_permutation(I first, S last, Comp comp = {}, Proj proj = {});
    template<bidirectional_range R, class Comp = ranges::less,
             class Proj = identity>
      requires sortable<iterator_t<R>, Comp, Proj>
      constexpr next_permutation_result<borrowed_iterator_t<R>>
        next_permutation(R&& r, Comp comp = {}, Proj proj = {});
  }
 
  template<class BidirectionalIter>
    constexpr bool prev_permutation(BidirectionalIter first,
                                    BidirectionalIter last);
  template<class BidirectionalIter, class Compare>
    constexpr bool prev_permutation(BidirectionalIter first,
                                    BidirectionalIter last, Compare comp);
 
  namespace ranges {
    template<class I>
      using prev_permutation_result = in_found_result<I>;
 
    template<bidirectional_iterator I, sentinel_for<I> S, class Comp = ranges::less,
             class Proj = identity>
      requires sortable<I, Comp, Proj>
      constexpr prev_permutation_result<I>
        prev_permutation(I first, S last, Comp comp = {}, Proj proj = {});
    template<bidirectional_range R, class Comp = ranges::less,
             class Proj = identity>
      requires sortable<iterator_t<R>, Comp, Proj>
      constexpr prev_permutation_result<borrowed_iterator_t<R>>
        prev_permutation(R&& r, Comp comp = {}, Proj proj = {});
  }
}

类模板 std::ranges::in_fun_result

namespace std::ranges {
  template<class I, class F>
  struct in_fun_result {
    [[no_unique_address]] I in;
    [[no_unique_address]] F fun;
 
    template<class I2, class F2>
      requires convertible_to<const I&, I2> && convertible_to<const F&, F2>
    constexpr operator in_fun_result<I2, F2>() const & {
      return {in, fun};
    }
 
    template<class I2, class F2>
      requires convertible_to<I, I2> && convertible_to<F, F2>
    constexpr operator in_fun_result<I2, F2>() && {
      return {std::move(in), std::move(fun)};
    }
  };
}

类模板 std::ranges::in_in_result

namespace std::ranges {
  template<class I1, class I2>
  struct in_in_result {
    [[no_unique_address]] I1 in1;
    [[no_unique_address]] I2 in2;
 
    template<class II1, class II2>
      requires convertible_to<const I1&, II1> && convertible_to<const I2&, II2>
    constexpr operator in_in_result<II1, II2>() const & {
      return {in1, in2};
    }
 
    template<class II1, class II2>
      requires convertible_to<I1, II1> && convertible_to<I2, II2>
    constexpr operator in_in_result<II1, II2>() && {
      return {std::move(in1), std::move(in2)};
    }
  };
}

类模板 std::ranges::in_out_result

namespace std::ranges {
  template<class I, class O>
  struct in_out_result {
    [[no_unique_address]] I in;
    [[no_unique_address]] O out;
 
    template<class I2, class O2>
      requires convertible_to<const I&, I2> && convertible_to<const O&, O2>
    constexpr operator in_out_result<I2, O2>() const & {
      return {in, out};
    }
 
    template<class I2, class O2>
      requires convertible_to<I, I2> && convertible_to<O, O2>
    constexpr operator in_out_result<I2, O2>() && {
      return {std::move(in), std::move(out)};
    }
  };
}

类模板 std::ranges::in_in_out_result

namespace std::ranges {
  template<class I1, class I2, class O>
  struct in_in_out_result {
    [[no_unique_address]] I1 in1;
    [[no_unique_address]] I2 in2;
    [[no_unique_address]] O  out;
 
    template<class II1, class II2, class OO>
      requires convertible_to<const I1&, II1> &&
               convertible_to<const I2&, II2> &&
               convertible_to<const O&, OO>
    constexpr operator in_in_out_result<II1, II2, OO>() const & {
      return {in1, in2, out};
    }
 
    template<class II1, class II2, class OO>
      requires convertible_to<I1, II1> &&
               convertible_to<I2, II2> &&
               convertible_to<O, OO>
    constexpr operator in_in_out_result<II1, II2, OO>() && {
      return {std::move(in1), std::move(in2), std::move(out)};
    }
  };
}

类模板 std::ranges::in_out_out_result

namespace std::ranges {
  template<class I, class O1, class O2>
  struct in_out_out_result {
    [[no_unique_address]] I  in;
    [[no_unique_address]] O1 out1;
    [[no_unique_address]] O2 out2;
 
    template<class II, class OO1, class OO2>
      requires convertible_to<const I&, II> &&
               convertible_to<const O1&, OO1> &&
               convertible_to<const O2&, OO2>
    constexpr operator in_out_out_result<II, OO1, OO2>() const & {
      return {in, out1, out2};
    }
 
    template<class II, class OO1, class OO2>
      requires convertible_to<I, II> &&
               convertible_to<O1, OO1> &&
               convertible_to<O2, OO2>
    constexpr operator in_out_out_result<II, OO1, OO2>() && {
      return {std::move(in), std::move(out1), std::move(out2)};
    }
  };
}

类模板 std::ranges::min_max_result

namespace std::ranges {
  template<class T>
  struct min_max_result {
    [[no_unique_address]] T min;
    [[no_unique_address]] T max;
 
    template<class T2>
      requires convertible_to<const T&, T2>
    constexpr operator min_max_result<T2>() const & {
      return {min, max};
    }
 
    template<class T2>
      requires convertible_to<T, T2>
    constexpr operator min_max_result<T2>() && {
      return {std::move(min), std::move(max)};
    }
  };
}

类模板 std::ranges::in_found_result

namespace std::ranges {
  template<class I>
  struct in_found_result {
    [[no_unique_address]] I in;
    bool found;
 
    template<class I2>
      requires convertible_to<const I&, I2>
    constexpr operator in_found_result<I2>() const & {
      return {in, found};
    }
    template<class I2>
      requires convertible_to<I, I2>
    constexpr operator in_found_result<I2>() && {
      return {std::move(in), found};
    }
  };
}
来自“https://zh.cppreference.com/mwiki/index.php?title=cpp/header/algorithm&oldid=72128”