深搜-迷宫

 package aha;

import java.util.Scanner;

public class migong_dfs {
	static int n;
	static int m;
	static int book[][] = new int[51][51];
	static int a[][] = new int[51][51];
	static int p;
	static int q;
	static int min = 999;

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		n = sc.nextInt();
		m = sc.nextInt();
		for (int i = 1; i <= n; i++) {
			for (int j = 1; j <= m; j++) {
				a[i][j] = sc.nextInt();
			}
		}
		p = sc.nextInt();
		q = sc.nextInt();
		book[1][1] = 1;
		dfs(1, 1, 0);
		System.out.println(min);
	}

	private static void dfs(int x, int y, int s) {
		int tx = 0, ty = 0;
		if (p == x && q == y) {
			if (min > s) {
				min = s;
			}
			return;
		}
		int next[][] = {{0,1},{1,0},{0,-1},{-1,0}};//{ { 1, 0 }, { 0,1 }, {-1,0 }, { 0,-1 } };
		for (int i = 0; i <= 3; i++) {
			tx = x + next[i][0];
			ty = y + next[i][1];

			if (tx < 1 || tx >n|| ty < 1 || ty > m) {
				continue;
			}
			if(book[tx][ty]==0&&a[tx][ty]==0){
				book[tx][ty]=1;
				
				dfs(tx,ty,s+1);
				book[tx][ty]=0;
			}
		}
		return ;
	}
}/*
5 4
0 0 1 0
0 0 0 0
0 0 1 0
0 1 0 0
0 0 0 1
3 4*/