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.

Example:

Given s = "Hello World",

return 5 as length("World") = 5.

Please make sure you try to solve this problem without using library functions. Make sure you only traverse the string once.

public class Solution {
    // DO NOT MODIFY THE LIST. IT IS READ ONLY
    public int lengthOfLastWord(final String A) {
        String str = A.trim();
        int len = 0;
        int pointer = str.length() - 1;
        while (pointer >= 0 && str.charAt(pointer) != ' ') {
            len++;
            pointer--;
        }
        return len;
    }
}