再探迷宫

迷宫最短路问题，用bfs会更快一点。

输入：

5 6
....S*
.**...
.*..*.
*..**.
.T....

输出：

7

代码如下：

import java.util.LinkedList;
import java.util.Queue;
import java.util.Scanner;

public class L2 {

	static int n, m, ans = 0;
	static char[][] map = new char[110][110];
	static boolean[][] vis = new boolean[110][110];
	static int[][] dir = { { -1, 0 }, { 0, -1 }, { 1, 0 }, { 0, 1 } };

	static boolean in(int x, int y) {
		return x >= 0 && x < n && y >= 0 && y < m;
	}

	static int bfs(int sx, int sy) {
		Queue<Node> q = new LinkedList<>();
		q.offer(new Node(sx, sy, 0));
		vis[sx][sy] = true;

		while (!q.isEmpty()) {
			Node now = q.poll();
			for (int i = 0; i < 4; i++) {
				int tx = now.x + dir[i][0];
				int ty = now.y + dir[i][1];
				if (in(tx, ty) && !vis[tx][ty] && map[tx][ty] != '*') {
					if (map[tx][ty] == 'T') {
						return now.d + 1;
					} else {
						vis[tx][ty] = true;
						q.offer(new Node(tx, ty, now.d + 1));
					}
				}
			}
		}
		return -1;
	}

	public static void main(String[] args) {
		// TODO Auto-generated method stub

		Scanner sc = new Scanner(System.in);
		n = sc.nextInt();
		m = sc.nextInt();
		for(int i=0;i<n;i++) {
			map[i]=sc.next().toCharArray();
		}
		for(int i=0;i<n;i++) {
			for(int j=0;j<m;j++) {
				if(map[i][j]=='S') {
					ans=bfs(i,j);
				}
			}
		}
		System.out.println(ans);
	}

}

class Node {
	int x, y, d;

	public Node(int x, int y, int d) {
		this.x = x;
		this.y = y;
		this.d = d;
	}
}