058. Length of Last Word

//Java solution01:
public class Solution {
    public int lengthOfLastWord(String s) {
        int len = s.length();
        if(s == null ||len == 0) {return 0;}
        
        int result = 0;
        
        for(int i = len - 1; i >= 0; i--){
            if (s.charAt(i) != ' ') { 
                result++;
            }
            else if(s.charAt(i) == ' ' && result != 0){
                return result;
            }
        }
        
        return result;
    }
}



//Java solution02:
public class Solution
{
    public int lengthOfLastWord(String s)
    {
        int len = s.length();
        int result = 0;
        int i = len - 1;
        
        if(s == null ||len == 0) {return 0;}

        // ignore the trailing whitespace
        while(i >= 0 && s.charAt(i) == ' ')
        {
            i--;
        }

        // count from tail until whitespace
        while(i >= 0 && s.charAt(i) != ' ')
        {
            i--;
            result++;
        }

        return result;
    }
}