切り捨て除算 (floor division)・切り上げ除算
(include/emthrm/math/division.hpp)

• View this file on GitHub
• Last update: 2023-02-23 21:59:12+09:00
• Include: #include "emthrm/math/division.hpp"

仕様

名前	戻り値
template <typename T, typename U> std::common_type_t<T, U> floor_div(const T a, const U b);	$\left\lfloor \frac{A}{B} \right\rfloor$
template <typename T, typename U> std::common_type_t<T, U> ceil_div(const T a, const U b);	$\left\lceil \frac{A}{B} \right\rceil$

参考文献

• https://twitter.com/noshi91/status/1439230342850695170
• https://github.com/NyaanNyaan/library/blob/6abcedf4fd779ce0a42a8b50d3cbbfa3ae5aef1a/misc/int_div.hpp

Code

#ifndef EMTHRM_MATH_DIVISION_HPP_
#define EMTHRM_MATH_DIVISION_HPP_

#include <cassert>
#include <type_traits>

namespace emthrm {

template <typename T, typename U>
std::common_type_t<T, U> floor_div(const T a, const U b) {
  assert(b != 0);
  return a / b - ((int{a < 0} ^ int{b < 0}) & int{a % b != 0});
}

template <typename T, typename U>
std::common_type_t<T, U> ceil_div(const T a, const U b) {
  assert(b != 0);
  return a / b + int{(a < 0) == (b < 0) && a % b != 0};
}

}  // namespace emthrm

#endif  // EMTHRM_MATH_DIVISION_HPP_

#line 1 "include/emthrm/math/division.hpp"



#include <cassert>
#include <type_traits>

namespace emthrm {

template <typename T, typename U>
std::common_type_t<T, U> floor_div(const T a, const U b) {
  assert(b != 0);
  return a / b - ((int{a < 0} ^ int{b < 0}) & int{a % b != 0});
}

template <typename T, typename U>
std::common_type_t<T, U> ceil_div(const T a, const U b) {
  assert(b != 0);
  return a / b + int{(a < 0) == (b < 0) && a % b != 0};
}

}  // namespace emthrm

Back to top page