leetcode Length of Last Word(easy) /java

import java.io.*;
import java.util.*;

public class Solution {
        public static int lengthOfLastWord(String s) {
        int r=0;
        int len=s.length();
        if(len==0)
            return 0;
        int i,j;
        char[] c=s.toCharArray();
        int flag=1;
        for(i=0;i<len;i++)
        {
            if(c[i]!=‘ ‘)
                flag=0;
        }
        if(flag==1)
            return 0;
        while(c[len-1]==‘ ‘)
            len--;
        for(i=len-1;i>=0;i--)
        {
            if(c[i]==‘ ‘)
                break;
            else
                r++;
        }

        return r;
    }
    public static void main(String[] args)
    {
        String a="   ";
        String b="Hello Wolrd lala   ";
        System.out.println(lengthOfLastWord(a));
        System.out.println(lengthOfLastWord(b));
    }
}