lintcode-easy-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.

Example

Given s = "Hello World", return 5.

Note

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

public class Solution {
    /**
     * @param s A string
     * @return the length of last word
     */
    public int lengthOfLastWord(String s) {
        // Write your code here
        if(s == null)
            return 0;
        
        String str = s.trim();
        if(str.length() == 0)   
            return 0;
        
        int count = 0;
        int index = str.length() - 1;
        
        while(index >= 0 && str.charAt(index) != ' '){
            count++;
            index--;
        }
        
        return count;
    }
}