258. Add Digits

258. Add Digits

DescriptionHintsSubmissionsDiscussSolution

DiscussPick One

---

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.

Follow up:
Could you do it without any loop/recursion in O(1) runtime?

Credits:

Special thanks to @jianchao.li.fighter for adding this problem and creating all test cases.

题意：

给定一个整数，求其各位之和，直到只剩下一位数

算法思路：

循环相加直到小于10即可

代码：

package easy;/*@author wchstrife@version 2017年7月22日下午11:03:12*/public class AddDigits {public int addDigits(int num) {while(num >9){num = num/10 + num%10;}return num;}}