2. リファレンス
3. unordered_map
4. unordered_multimap
5. load_factor

最終更新日時: 2026年09月19日 21時31分51秒 (JST)
rotarymars が更新

履歴 編集

std::unordered_multimap::load_factor(C++11)

float load_factor() const noexcept;           // (1) C++11
constexpr float load_factor() const noexcept; // (1) C++26

size() / bucket_count()

#include <iostream>
#include <unordered_map>

int main()
{
  std::unordered_multimap<int,int> um;

  um.emplace(1, 1);
  um.emplace(1, 1);
  um.emplace(2, 2);
  um.emplace(3, 3);

  std::cout << "current max_load_factor: " << um.max_load_factor() << std::endl;
  std::cout << "current size: " << um.size() << std::endl;
  std::cout << "current bucket_count: " << um.bucket_count() << std::endl;
  std::cout << "current load_factor: " << um.load_factor() << std::endl; // (size / bucket_count)
  std::cout << std::endl;

  return 0;
}

current max_load_factor: 1
current size: 4
current bucket_count: 8
current load_factor: 0.5