Description

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.

Solution

太简单的题了。

Iteration

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