Grid segmentation

package lanqiao;

/**
 * Created by ministrong on 2020/2/27.
 *
  title ： Grid segmentation 

 6x6 Of the lattice , Cut in two along the edge of the grid .
  The shape of the two parts should be exactly the same .

  Pictured ：p1.png, p2.png, p3.png  It's a feasible segmentation .

  Try to calculate ：
  Including this 3 The method of seed division is inside , How many different segmentation methods are there .
  Be careful ： Rotationally symmetric belongs to the same segmentation method .

  Please submit the integer , Don't fill in any superfluous content or explanatory text .

 answer ：509
 */

import java.util.ArrayList;
import java.util.Arrays;

/**
 *
 *  Consider cutting grids to achieve , From the center point , The pointer a Take a step , The pointer b Take a step in its central symmetry , until a Go to the border , here b Also at the same time to the border .
 *  The cut figure must be feasible , Just divide the final result by 4, Because I want to go to the rotationally symmetrical repetition 
 *
 * Ps： The pointer cannot go back 
 *
 */
public class Q4_2017_8_fanggefenge {
    public static int res=0;
    public static void main(String[] args) {


        int[][] a=new int[7][7];
        compute(a,3,3);

        System.out.println(res/4);


    }

    public static void compute(int[][] a,int i,int j){
        if(i>=6 || i<=0 || j>=6 || j<=0) res++;
        else{
            if(a[i][j]==1) return;
            else{
                a[i][j]=1;
                a[6-i][6-j]=1;
                compute(a,i+1,j);
                compute(a,i-1,j);
                compute(a,i,j+1);
                compute(a,i,j-1);
                a[i][j]=0;
                a[6-i][6-j]=0;
            }


        }

    }


}