LeetCode之Add Digits

1、题目

Given a non-negative integer num, repeatedly add all its digits until the result has only one digit.

For example:

Given num = 38, the process is like: 3 + 8 = 11, 1 + 1 = 2. Since 2 has only one digit, return it.

2、代码实现

public class Solution {
   public int getAllSum(int val) {
		int sum = 0;
		while (val > 0) {
			sum += val % 10;
			val /= 10;
		}
		return sum;
	}
	
	public  int addDigits(int num) {
		if (num <= 0) 
			return 0;
		while (num >= 10) {
			num = getAllSum(num);
		}
		return num;
	}
}