标准库头文件 <numeric>

namespace std {
  // 累加
  template<class InputIt, class T>
    constexpr T accumulate(InputIt first, InputIt last, T init);
  template<class InputIt, class T, class BinaryOperation>
    constexpr T accumulate(InputIt first, InputIt last, T init, BinaryOperation binary_op);
 
  // 规约
  template<class InputIt>
    constexpr typename iterator_traits<InputIt>::value_type
      reduce(InputIt first, InputIt last);
  template<class InputIt, class T>
    constexpr T reduce(InputIt first, InputIt last, T init);
  template<class InputIt, class T, class BinaryOperation>
    constexpr T reduce(InputIt first, InputIt last, T init, BinaryOperation binary_op);
  template<class ExecutionPolicy, class ForwardIt>
    typename iterator_traits<ForwardIt>::value_type
      reduce(ExecutionPolicy&& exec,
             ForwardIt first, ForwardIt last);
  template<class ExecutionPolicy, class ForwardIt, class T>
    T reduce(ExecutionPolicy&& exec,
             ForwardIt first, ForwardIt last, T init);
  template<class ExecutionPolicy, class ForwardIt, class T, class BinaryOperation>
    T reduce(ExecutionPolicy&& exec,
             ForwardIt first, ForwardIt last, T init, BinaryOperation binary_op);
 
  // 内积
  template<class InputIt1, class InputIt2, class T>
    constexpr T inner_product(InputIt1 first1, InputIt1 last1,
                              InputIt2 first2, T init);
  template<class InputIt1, class InputIt2, class T,
           class BinaryOperation1, class BinaryOperation2>
    constexpr T inner_product(InputIt1 first1, InputIt1 last1,
                              InputIt2 first2, T init,
                              BinaryOperation1 binary_op1,
                              BinaryOperation2 binary_op2);
 
  // 变换规约
  template<class InputIt1, class InputIt2, class T>
    constexpr T transform_reduce(InputIt1 first1, InputIt1 last1,
                                 InputIt2 first2,
                                 T init);
  template<class InputIt1, class InputIt2, class T,
           class BinaryOperation1, class BinaryOperation2>
    constexpr T transform_reduce(InputIt1 first1, InputIt1 last1,
                                 InputIt2 first2,
                                 T init,
                                 BinaryOperation1 binary_op1,
                                 BinaryOperation2 binary_op2);
  template<class InputIt, class T,
           class BinaryOperation, class UnaryOperation>
    constexpr T transform_reduce(InputIt first, InputIt last,
                                 T init,
                                 BinaryOperation binary_op, UnaryOperation unary_op);
  template<class ExecutionPolicy,
           class ForwardIt1, class ForwardIt2, class T>
    T transform_reduce(ExecutionPolicy&& exec,
                       ForwardIt1 first1, ForwardIt1 last1,
                       ForwardIt2 first2,
                       T init);
  template<class ExecutionPolicy,
           class ForwardIt1, class ForwardIt2, class T,
           class BinaryOperation1, class BinaryOperation2>
    T transform_reduce(ExecutionPolicy&& exec,
                       ForwardIt1 first1, ForwardIt1 last1,
                       ForwardIt2 first2,
                       T init,
                       BinaryOperation1 binary_op1,
                       BinaryOperation2 binary_op2);
  template<class ExecutionPolicy,
           class ForwardIt, class T,
           class BinaryOperation, class UnaryOperation>
    T transform_reduce(ExecutionPolicy&& exec,
                       ForwardIt first, ForwardIt last,
                       T init,
                       BinaryOperation binary_op, UnaryOperation unary_op);
 
  // 部分和
  template<class InputIt, class OutputIt>
    constexpr OutputIt partial_sum(InputIt first,
                                   InputIt last,
                                   OutputIt result);
  template<class InputIt, class OutputIt, class BinaryOperation>
    constexpr OutputIt partial_sum(InputIt first,
                                   InputIt last,
                                   OutputIt result,
                                   BinaryOperation binary_op);
 
  // 排除扫描
  template<class InputIt, class OutputIt, class T>
    constexpr OutputIt exclusive_scan(InputIt first, InputIt last,
                                      OutputIt result,
                                      T init);
  template<class InputIt, class OutputIt, class T, class BinaryOperation>
    constexpr OutputIt exclusive_scan(InputIt first, InputIt last,
                                      OutputIt result,
                                      T init, BinaryOperation binary_op);
  template<class ExecutionPolicy, class ForwardIt1, class ForwardIt2, class T>
    ForwardIt2 exclusive_scan(ExecutionPolicy&& exec,
                              ForwardIt1 first, ForwardIt1 last,
                              ForwardIt2 result,
                              T init);
  template<class ExecutionPolicy, class ForwardIt1, class ForwardIt2, class T,
           class BinaryOperation>
    ForwardIt2 exclusive_scan(ExecutionPolicy&& exec,
                              ForwardIt1 first, ForwardIt1 last,
                              ForwardIt2 result,
                              T init, BinaryOperation binary_op);
 
  // 包含扫描
  template<class InputIt, class OutputIt>
    constexpr OutputIt inclusive_scan(InputIt first, InputIt last, OutputIt result);
  template<class InputIt, class OutputIt, class BinaryOperation>
    constexpr OutputIt inclusive_scan(InputIt first, InputIt last,
                                      OutputIt result,
                                      BinaryOperation binary_op);
  template<class InputIt, class OutputIt, class BinaryOperation, class T>
    constexpr OutputIt inclusive_scan(InputIt first, InputIt last,
                                      OutputIt result,
                                      BinaryOperation binary_op, T init);
  template<class ExecutionPolicy, class ForwardIt1, class ForwardIt2>
    ForwardIt2 inclusive_scan(ExecutionPolicy&& exec,
                              ForwardIt1 first, ForwardIt1 last,
                              ForwardIt2 result);
  template<class ExecutionPolicy, class ForwardIt1, class ForwardIt2,
           class BinaryOperation>
    ForwardIt2 inclusive_scan(ExecutionPolicy&& exec,
                              ForwardIt1 first, ForwardIt1 last,
                              ForwardIt2 result,
                              BinaryOperation binary_op);
  template<class ExecutionPolicy, class ForwardIt1, class ForwardIt2,
           class BinaryOperation, class T>
    ForwardIt2 inclusive_scan(ExecutionPolicy&& exec,
                              ForwardIt1 first, ForwardIt1 last,
                              ForwardIt2 result,
                              BinaryOperation binary_op, T init);
 
  // 变换排除扫描
  template<class InputIt, class OutputIt, class T,
           class BinaryOperation, class UnaryOperation>
    constexpr OutputIt transform_exclusive_scan(InputIt first, InputIt last,
                                                OutputIt result,
                                                T init,
                                                BinaryOperation binary_op,
                                                UnaryOperation unary_op);
  template<class ExecutionPolicy,
           class ForwardIt1, class ForwardIt2, class T,
           class BinaryOperation, class UnaryOperation>
    ForwardIt2 transform_exclusive_scan(ExecutionPolicy&& exec,
                                        ForwardIt1 first, ForwardIt1 last,
                                        ForwardIt2 result,
                                        T init,
                                        BinaryOperation binary_op,
                                        UnaryOperation unary_op);
 
  // 变换包含扫描
  template<class InputIt, class OutputIt,
           class BinaryOperation, class UnaryOperation>
    constexpr OutputIt transform_inclusive_scan(InputIt first, InputIt last,
                                                OutputIt result,
                                                BinaryOperation binary_op,
                                                UnaryOperation unary_op);
  template<class InputIt, class OutputIt,
           class BinaryOperation, class UnaryOperation, class T>
    constexpr OutputIt transform_inclusive_scan(InputIt first, InputIt last,
                                                OutputIt result,
                                                BinaryOperation binary_op,
                                                UnaryOperation unary_op,
                                                T init);
  template<class ExecutionPolicy,
           class ForwardIt1, class ForwardIt2,
           class BinaryOperation, class UnaryOperation>
    ForwardIt2 transform_inclusive_scan(ExecutionPolicy&& exec,
                                        ForwardIt1 first, ForwardIt1 last,
                                        ForwardIt2 result,
                                        BinaryOperation binary_op,
                                        UnaryOperation unary_op);
  template<class ExecutionPolicy,
           class ForwardIt1, class ForwardIt2,
           class BinaryOperation, class UnaryOperation, class T>
    ForwardIt2 transform_inclusive_scan(ExecutionPolicy&& exec,
                                        ForwardIt1 first, ForwardIt1 last,
                                        ForwardIt2 result,
                                        BinaryOperation binary_op,
                                        UnaryOperation unary_op,
                                        T init);
 
  // 相邻差
  template<class InputIt, class OutputIt>
    constexpr OutputIt adjacent_difference(InputIt first, InputIt last,
                                           OutputIt result);
  template<class InputIt, class OutputIt, class BinaryOperation>
    constexpr OutputIt adjacent_difference(InputIt first, InputIt last,
                                           OutputIt result,
                                           BinaryOperation binary_op);
  template<class ExecutionPolicy, class ForwardIt1, class ForwardIt2>
    ForwardIt2 adjacent_difference(ExecutionPolicy&& exec,
                                   ForwardIt1 first, ForwardIt1 last,
                                   ForwardIt2 result);
  template<class ExecutionPolicy, class ForwardIt1, class ForwardIt2,
           class BinaryOperation>
    ForwardIt2 adjacent_difference(ExecutionPolicy&& exec,
                                   ForwardIt1 first, ForwardIt1 last,
                                   ForwardIt2 result,
                                   BinaryOperation binary_op);
 
  // iota
  template<class ForwardIt, class T>
    constexpr void iota(ForwardIt first, ForwardIt last, T value);
 
  // 最大公约数
  template<class M, class N>
    constexpr common_type_t<M, N> gcd(M m, N n);
 
  // 最小公倍数
  template<class M, class N>
    constexpr common_type_t<M, N> lcm(M m, N n);
 
  // 中点
  template<class T>
    constexpr T midpoint(T a, T b) noexcept;
  template<class T>
    constexpr T* midpoint(T* a, T* b);
}