58. 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:

Input: "Hello World"
Output: 5

public class Solution {
    public static int lengthOfLastWord(String s) {
        if (s == null || s.length() == 0) return 0;
        int n = s.length()-1, counter = 0;
        while (n >= 0) {
            if (s.charAt(n) != ' ') counter++;
            if (s.charAt(n) == ' ' && counter > 0) break;
            n--;
        }
        return counter;
    }
}

class Solution {
    public int lengthOfLastWord(String s) {
        String[] str = s.split(" ");
        int count = str.length;
        if(count == 0) 
            return 0;
        return str[count-1].length();
    }
}

class Solution {
    public int lengthOfLastWord(String s) {
        s = s.trim();
		if (s.isEmpty()) {
			return 0;
		}
		int lastWordStartIndex = s.lastIndexOf(" ");
		int lastWordEndIndex = s.length() - 1;
		return lastWordEndIndex - lastWordStartIndex;
    }
}