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.

First use trim() to remove the starting and trailing spaces. Then if you see a whitespace clear the last word, otherwise append the string to the last word.

public int lengthOfLastWord(String s) {
        if (s==null||s.isEmpty()) {
            return 0;
        }

        StringBuilder sb = new StringBuilder();
        s = s.trim();
        for (int i=0; i<s.length(); i++) {
            if (s.charAt(i)!=' ') {
                sb.append(s.charAt(i));
            } else {
                sb.setLength(0);
            }
        }

        return sb.length();
    }