Popcount
(misc/popcount.hpp)

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• Last update: 2025-12-31 07:11:44+09:00
• Include: #include "misc/popcount.hpp"

popcount

int popcount(T x)

立っているビットの個数を返します。

Required by

• my_template.hpp
• my_template_int128.hpp

Verified with

• misc/test/bit_operation.test.cpp

Code

#pragma once

#if __cplusplus >= 202002L
#include <bit>
#endif

// popcount
// (000, 001, 010, 011, 100) -> (0, 1, 1, 2, 1)
#if __cplusplus >= 202002L
using std::popcount;
#else
int popcount(unsigned int x) { return __builtin_popcount(x); }
int popcount(unsigned long long int x) { return __builtin_popcountll(x); }
#endif
int popcount(int x) { return popcount((unsigned int)(x)); }
int popcount(long long int x) { return popcount((unsigned long long int)(x)); }

#line 2 "misc/popcount.hpp"

#if __cplusplus >= 202002L
#include <bit>
#endif

// popcount
// (000, 001, 010, 011, 100) -> (0, 1, 1, 2, 1)
#if __cplusplus >= 202002L
using std::popcount;
#else
int popcount(unsigned int x) { return __builtin_popcount(x); }
int popcount(unsigned long long int x) { return __builtin_popcountll(x); }
#endif
int popcount(int x) { return popcount((unsigned int)(x)); }
int popcount(long long int x) { return popcount((unsigned long long int)(x)); }

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