58. Length of Last Word

Given a string s consists of upper/lower-case alphabets and empty space characters ' ', return the length of last word in the string.

If the last word does not exist, return 0.

Note: A word is defined as a character sequence consists of non-space characters only.

For example, 
Given s = "Hello World",

return 5.

public class Solution {    public int lengthOfLastWord(String s) {        if(s == null || s.length() == 0){            return 0;        }        int res = 0;        for(int i=s.length() - 1; i>=0; i--){            if(s.charAt(i) != ' '){                res++;            }            if(s.charAt(i) == ' ' && res != 0){                break;            }        }        return res;    }}

注意判断最后一个是空格的情况