桁和
(library/number/digit_sum.hpp)

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• Last update: 2026-01-07 21:05:45+09:00
• Include: #include "library/number/digit_sum.hpp"

桁和

できること

• 整数の、N進数での各桁の和を求める

計算量

$O(logN)$

使い方

int sum = digit_sum(N, 10);

Verified with

• 桁和のテスト (tests/number.digit_sum.test.cpp)

Code

#pragma once
int digit_sum(int N, int base_number = 10) {
    int res = 0;
    while (N != 0) {
        res += N % base_number;
        N /= base_number;
    }
    return res;
}

#line 2 "library/number/digit_sum.hpp"
int digit_sum(int N, int base_number = 10) {
    int res = 0;
    while (N != 0) {
        res += N % base_number;
        N /= base_number;
    }
    return res;
}

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