58. Length of Last Word

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.

Solution

public class Solution {

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

        int start = s.length() - 1;
        while (start >= 0 && s.charAt(start) == ' ') {
            start--;
        }

        if (start == -1) {
            return 0;
        }

        int result = 0;
        for (int i = start; i >= 0; i--) {
            if (s.charAt(i) == ' ') {
                break;
            } else {
                result++;
            }
        }

        return result;
    }
}