qunar2019馬在8*8棋盤上從A到B最短需要幾步（DFS）

package com.qunar;

import java.util.Scanner;

public class Main21 {
	private static Scanner input =new Scanner(System.in);
	private static int x1=input.nextInt();
	private static int y1=input.nextInt();
	private static int x2=input.nextInt();
	private static int y2=input.nextInt();
	private static int res=Integer.MAX_VALUE;
	private static boolean[][] marked=new boolean[9][9];
	private static int[][] dir=new int[][] {{1,2},{1,-2},{-1,2},{-1,-2},
											{2,1},{2,-1},{-2,1},{-2,-1}};

	public static void main(String[] args) {
		// TODO Auto-generated method stub
		int step=0;
		dfs(x1,y1,0);
		System.out.println(res);

	}

	private static void dfs(int x, int y,int step) {
		// TODO Auto-generated method stub
		if (step<res) {
			if(x==x2&&y==y2) {
				res=step;
				return;
			}
			else {
				for (int i=0;i<8;i++) {
					int tmpx=x+dir[i][0];
					int tmpy=y+dir[i][1];
					if(tmpx>=1&&tmpx<=8&&tmpy>=1&&tmpy<=8&&!marked[tmpx][tmpy]) {
						marked[tmpx][tmpy]=true;
						dfs(tmpx,tmpy,step+1);
						marked[tmpx][tmpy]=false;
					}
				}
			}
			
		}
	}

}