Leetcode 258. Add Digits

文章作者：Tyan
博客：noahsnail.com  |  CSDN  |  简书

1. Description

2. Solution

• Version 1

class Solution {
public:
    int addDigits(int num) {
        int n = num;
        while(n > 9) {
            n = calDigits(n);
        }
        return n;
    }

private:
    int calDigits(int m) {
        int sum = 0;
        while(m) {
            int r = m % 10;
            sum += r;
            m = m / 10;
        }
        return sum;
    }
};

• Version 2

class Solution {
public:
    int addDigits(int num) {
        if(num == 0) {
            return 0;
        }
        int res = num % 9;
        return res==0?9:res;
    }
};

Reference

1. https://leetcode.com/problems/add-digits/description/