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 p = s.length()-1;
        while(p >=0 && s.charAt(p) == ' ') p--;
        if(p < 0) return 0;
        int res = 0;
        while( p >=0 && s.charAt(p) != ' '){
            p--;
            res++;
        }
        return res;
    }
}