# 标准库头文件 <algorithm>

< cpp‎ | header

此头文件是算法库的一部分。

### 包含
<initializer_list> (C++11) | std::initializer_list 类模板
### 类
定义于命名空间 `std::ranges`
##### 返回类型
ranges::in_fun_result (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)
ranges::in_in_result (C++20) | 提供存储二个迭代器为单个单元的方式 (类模板)
ranges::in_out_result (C++20) | 提供存储二个迭代器为单个单元的方式 (类模板)
ranges::in_in_out_result (C++20) | 提供存储三个迭代器为单个单元的方式 (类模板)
ranges::in_out_out_result (C++20) | 提供存储三个迭代器为单个单元的方式 (类模板)
ranges::min_max_result (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)
ranges::in_found_result (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
all_of any_of none_of (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)
for_each | 应用函数到范围中的元素 (函数模板)
for_each_n (C++17) | 应用一个函数对象到序列的前 n 个元素 (函数模板)
count count_if | 返回满足指定判别标准的元素数 (函数模板)
mismatch | 寻找两个范围出现不同的首个位置 (函数模板)
find find_if find_if_not (C++11) | 寻找首个满足特定判别标准的元素 (函数模板)
find_end | 在特定范围中寻找最后出现的元素序列 (函数模板)
find_first_of | 搜索元素集合中的任意元素 (函数模板)
adjacent_find | 查找首对相邻的相同（或满足给定谓词的）元素 (函数模板)
search | 搜索一个元素范围 (函数模板)
search_n | 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
copy copy_if (C++11) | 将某一范围的元素复制到一个新的位置 (函数模板)
copy_n (C++11) | 将一定数目的元素复制到一个新的位置 (函数模板)
copy_backward | 按从后往前的顺序复制一个范围内的元素 (函数模板)
move (C++11) | 将某一范围的元素移动到一个新的位置 (函数模板)
move_backward (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)
fill | 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)
fill_n | 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)
transform | 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)
generate | 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)
generate_n | 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)
remove remove_if | 移除满足特定判别标准的元素 (函数模板)
remove_copy remove_copy_if | 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)
replace replace_if | 将所有满足特定判别标准的值替换为另一个值 (函数模板)
replace_copy replace_copy_if | 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)
swap | 交换两个对象的值 (函数模板)
swap_ranges | 交换两个范围的元素 (函数模板)
iter_swap | 交换两个迭代器所指向的元素 (函数模板)
reverse | 逆转范围中的元素顺序 (函数模板)
reverse_copy | 创建一个范围的逆向副本 (函数模板)
rotate | 旋转范围中的元素顺序 (函数模板)
rotate_copy | 复制并旋转元素范围 (函数模板)
shift_left shift_right (C++20) | 迁移范围中的元素 (函数模板)
random_shuffle shuffle (C++17 前)(C++11) | 随机重排范围中的元素 (函数模板)
sample (C++17) | 从一个序列中随机选择 n 个元素 (函数模板)
unique | 移除范围内的连续重复元素 (函数模板)
unique_copy | 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
is_partitioned (C++11) | 判断范围是否已按给定的谓词划分 (函数模板)
partition | 将范围中的元素分为两组 (函数模板)
partition_copy (C++11) | 复制一个范围，将各元素分为两组 (函数模板)
stable_partition | 将元素分为两组，同时保留其相对顺序 (函数模板)
partition_point (C++11) | 定位已划分范围的划分点 (函数模板)
##### 排序操作
is_sorted (C++11) | 检查范围是否已按升序排列 (函数模板)
is_sorted_until (C++11) | 找出最大的已排序子范围 (函数模板)
sort | 将范围按升序排序 (函数模板)
partial_sort | 排序一个范围的前 N 个元素 (函数模板)
partial_sort_copy | 对范围内的元素进行复制并部分排序 (函数模板)
stable_sort | 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)
nth_element | 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
lower_bound | 返回指向第一个不小于给定值的元素的迭代器 (函数模板)
upper_bound | 返回指向第一个大于给定值的元素的迭代器 (函数模板)
binary_search | 确定元素是否存在于某范围中 (函数模板)
equal_range | 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
merge | 归并两个已排序的范围 (函数模板)
inplace_merge | 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
includes | 若一个序列是另一个的子列则返回 true (函数模板)
set_difference | 计算两个集合的差集 (函数模板)
set_intersection | 计算两个集合的交集 (函数模板)
set_symmetric_difference | 计算两个集合的对称差 (函数模板)
set_union | 计算两个集合的并集 (函数模板)
##### 堆操作
is_heap | 检查给定范围是否为一个最大堆 (函数模板)
is_heap_until (C++11) | 查找能成为最大堆的最大子范围 (函数模板)
make_heap | 从一个元素范围创建出一个最大堆 (函数模板)
push_heap | 将一个元素加入到一个最大堆 (函数模板)
pop_heap | 从最大堆中移除最大元素 (函数模板)
sort_heap | 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
max | 返回各给定值中的较大者 (函数模板)
max_element | 返回范围内的最大元素 (函数模板)
min | 返回各给定值中的较小者 (函数模板)
min_element | 返回范围内的最小元素 (函数模板)
minmax (C++11) | 返回两个元素的较小和较大者 (函数模板)
minmax_element (C++11) | 返回范围内的最小元素和最大元素 (函数模板)
clamp (C++17) | 在一对边界值间夹逼一个值 (函数模板)
##### 比较操作
equal | 确定两个元素集合是否是相同的 (函数模板)
lexicographical_compare | 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)
lexicographical_compare_three_way (C++20) | 用三路比较比较两个范围 (函数模板)
##### 排列操作
is_permutation (C++11) | 判断一个序列是否为另一个序列的排列 (函数模板)
next_permutation | 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)
prev_permutation | 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
定义于命名空间 `std::ranges`
##### 不修改序列的操作
ranges::all_of ranges::any_of ranges::none_of (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)
ranges::for_each (C++20) | 应用函数到范围中的元素 (niebloid)
ranges::for_each_n (C++20) | 应用函数对象到序列的首 n 个元素 (niebloid)
ranges::count ranges::count_if (C++20)(C++20) | 返回满足指定判别标准的元素数 (niebloid)
ranges::mismatch (C++20) | 寻找两个范围出现不同的首个位置 (niebloid)
ranges::find ranges::find_if ranges::find_if_not (C++20)(C++20)(C++20) | 寻找首个满足特定判别标准的元素 (niebloid)
ranges::find_end (C++20) | 在特定范围中寻找最后出现的元素序列 (niebloid)
ranges::find_first_of (C++20) | 搜索元素集合中的任一元素 (niebloid)
ranges::adjacent_find (C++20) | 查找首对相邻的相同（或满足给定谓词的）元素 (niebloid)
ranges::search (C++20) | 搜索一个元素范围 (niebloid)
ranges::search_n (C++20) | 在范围中搜索一定量的某个元素的连续副本 (niebloid)
ranges::starts_with (C++23) | 检查一个范围是否始于另一范围 (niebloid)
ranges::ends_with (C++23) | 检查一个范围是否终于另一范围 (niebloid)
##### 修改序列的操作
ranges::copy ranges::copy_if (C++20)(C++20) | 将某一范围的元素复制到一个新的位置 (niebloid)
ranges::copy_n (C++20) | 将一定数目的元素复制到一个新的位置 (niebloid)
ranges::copy_backward (C++20) | 按从后往前的顺序复制一个范围内的元素 (niebloid)
ranges::move (C++20) | 将某一范围的元素移动到一个新的位置 (niebloid)
ranges::move_backword (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)
ranges::fill (C++20) | 将一个给定值复制赋值给一个范围内的每个元素 (niebloid)
ranges::fill_n (C++20) | 将一个值复制赋值给一定量的元素 (niebloid)
ranges::transform (C++20) | 将一个函数应用于某一范围的各个元素 (niebloid)
ranges::generate (C++20) | 保存函数结果到一个范围中 (niebloid)
ranges::generate_n (C++20) | 保存 N 次函数应用的结果 (niebloid)
ranges::remove ranges::remove_if (C++20)(C++20) | 移除满足特定判别标准的元素 (niebloid)
ranges::remove_copy ranges::remove_copy_if (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)
ranges::replace ranges::replace_if (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)
ranges::replace_copy ranges::replace_copy_if (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)
ranges::swap_ranges (C++20) | 交换两个范围的元素 (niebloid)
ranges::reverse (C++20) | 逆转范围中的元素顺序 (niebloid)
ranges::revserse_copy (C++20) | 创建一个范围的逆向副本 (niebloid)
ranges::rotate (C++20) | 旋转范围中的元素顺序 (niebloid)
ranges::rotate_copy (C++20) | 复制并旋转元素范围 (niebloid)
ranges::sample (C++20) | 从序列中随机选择 n 个元素 (niebloid)
ranges::shuffle (C++20) | 随机重排范围中的元素 (niebloid)
ranges::unique (C++20) | 移除范围中的连续重复元素 (niebloid)
ranges::unique_copy (C++20) | 创建某范围的不含连续重复元素的副本 (niebloid)
##### 划分操作
ranges::is_partitioned (C++20) | 判断范围是否已按给定的谓词划分 (niebloid)
ranges::partition (C++20) | 将范围中的元素分为二组 (niebloid)
ranges::partition_copy (C++20) | 复制一个范围，将各元素分为二组 (niebloid)
ranges::stable_partition (C++20) | 将元素分成二组，同时保持其相对顺序 (niebloid)
ranges::partition_point (C++20) | 定位已划分范围的划分点 (niebloid)
##### 排序操作
ranges::is_sorted (C++20) | 检查范围是否以升序排序 (niebloid)
ranges::is_sorted_until (C++20) | 寻找最大的已排序子范围 (niebloid)
ranges::sort (C++20) | 将范围按升序排序 (niebloid)
ranges::partial_sort (C++20) | 排序一个范围的前 N 个元素 (niebloid)
ranges::partial_sort_copy (C++20) | 对范围内的元素进行复制并部分排序 (niebloid)
ranges::stable_sort (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)
ranges::nth_element (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
ranges::lower_bound (C++20) | 返回指向首个不小于给定值的元素的迭代器 (niebloid)
ranges::upper_bound (C++20) | 返回指向首个大于某值的元素的迭代器 (niebloid)
ranges::binary_search (C++20) | 确定元素是否存在于某范围中 (niebloid)
ranges::equal_ranges (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
ranges::merge (C++20) | 归并二个已排序范围 (niebloid)
ranges::inplace_merge (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
ranges::includes (C++20) | 若一个序列是另一个的子列则返回 `true` (niebloid)
ranges::set_difference (C++20) | 计算两个集合的差集 (niebloid)
ranges::set_intersection (C++20) | 计算两个集合的交集 (niebloid)
ranges::set_symmetric_difference (C++20) | 计算两个集合的对称差 (niebloid)
ranges::set_union (C++20) | 计算两个集合的并集 (niebloid)
##### 堆操作
ranges::is_heap (C++20) | 检查给定范围是否为最大堆 (niebloid)
ranges::is_heap_until (C++20) | 寻找能成为最大堆的最大子范围 (niebloid)
ranges::make_heap (C++20) | 从一个元素范围创建出一个最大堆 (niebloid)
ranges::push_heap (C++20) | 将一个元素加入到一个最大堆 (niebloid)
ranges::pop_heap (C++20) | 从最大堆中移除最大元素 (niebloid)
ranges::sort_heap (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
ranges::max (C++20) | 返回给定值的较大者 (niebloid)
ranges::max_element (C++20) | 返回范围中的最大元素 (niebloid)
ranges::min (C++20) | 返回给定值的较小者 (niebloid)
ranges::min_element (C++20) | 返回范围中的最小元素 (niebloid)
ranges::minmax (C++20) | 返回两个元素的较小和较大者 (niebloid)
ranges::minmax_element (C++20) | 返回范围中的最小和最大元素 (niebloid)
ranges::clamp (C++20) | 在一对边界值间夹一个值 (niebloid)
##### 比较操作
ranges::equal (C++20) | 确定两个元素集合是否是相同的 (niebloid)
ranges::lexicographical_compare (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
ranges::is_permutation (C++20) | 确定一个序列是否为另一序列的重排 (niebloid)
ranges::next_permutation (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};
        }
      };
    }