天天一道LeetCode--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) {
       s=s.trim();
       int lastIndex=s.lastIndexOf(' ')+1;
       return s.length()-lastIndex;
    }
}