codeforces 287A IQTest program in java

IQTest.java

import java.util.Scanner;
public class IQTest
{
    public static void main(String[] args)
    {
        Scanner z=new Scanner(System.in);
        String[] s=new String[4];
        char[][] a=new char[4][4];
        for(int i=0;i<4;i++)
            s[i]=z.nextLine();
        for(int i=0;i<4;i++){
            for(int j=0;j<4;j++)
                a[i][j]=s[i].charAt(j);
        }
        int k=0;
        boolean flag=false;
        for(int i=0;i<3;i++){
            for(int j=0;j<3;j++){
                k=0;
                if(a[i][j]!=a[i][j+1])
                    k++;
                if(a[i][j]!=a[i+1][j])
                    k++;
                if(a[i][j]!=a[i+1][j+1])
                    k++;
                if(k<=1 || k==3){
                    flag=true;
                    break;
                }
            }
        }
        if(flag)
            System.out.println("YES");
        else
            System.out.println("NO");
    }
}