周清城的博客

P344倒置字符串  这里说的是字符串，并不是一个数组，所以在进行倒序之前，要先将它转化为字符数组，可以用头toCharArray（），  这里可以写成char [ ] word=s.toCharArray(); 




public class Solution { /** * 给定整数不断将它的各位相加，直到相加的结果小于10，返回结果

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