pow.hpp

#pragma once
 
#include <cstdint>
#include <functional>
 
namespace cplib {
 
template <typename T, typename Op = std::multiplies<T>>
constexpr T pow(T base, uint64_t exp, Op&& op = {}) {
  T res(1);
  while (exp) {
    if (exp & 1) {
      res = op(res, base);
    }
    base = op(base, base);
    exp >>= 1;
  }
  return res;
}
 
}  // namespace cplib