题目描述：
...11111111111111111111111111111 11.111111........1111111111.1111 11.111111..111.11111111.....1111 11.11111111111.1111111111.111111 11.111111.................111111 11.111111.11111111111.11111.1111 11.111111.11111111111.11111..111 11..........111111111.11111.1111 11111.111111111111111.11....1111 11111.111111111111111.11.11.1111 11111.111111111111111.11.11.1111 111...111111111111111.11.11.1111 111.11111111111111111....11.1111 111.11111111111111111111111.1111 111.1111.111111111111111......11 111.1111.......111111111.1111.11 111.1111.11111.111111111.1111.11 111......11111.111111111.1111111 11111111111111.111111111.111...1 11111111111111...............1.1 111111111111111111111111111111.. 如上图的迷宫，入口，出口分别：左上角，右下角 "1"是墙壁，"."是通路 求最短需要走多少步？
代码实现：
1 import java.util.LinkedList; 2 import java.util.Queue; 3 import java.util.Scanner; 4 5 public class 图的bfs_迷宫 { 6 public static void main(String[] args) { 7 Scanner scanner = new Scanner(System.in); 8 int m = 21; 9 int n = 32; 10 char[][] graph = new char[m][n]; 11 int[][] vis = new int[m][n];// 标记哪些点已经被访问 12 Queue<Node> queue = new LinkedList<>(); 13 for (int i = 0; i < m; i++) { 14 graph[i] = scanner.nextLine().toCharArray(); 15 } 16 // for (int j = 0; j < graph.length; j++) { 17 // for (int k = 0; k < graph[j].length; k++) { 18 // System.out.print(graph[j][k]); 19 // } 20 // System.out.println(); 21 // } 22 23 Node start = new Node(0, 0, 0); 24 queue.add(start); 25 while (!queue.isEmpty()) { 26 Node poll = queue.poll(); 27 int x = poll.x; 28 int y = poll.y; 29 int deep = poll.depth; 30 vis[x][y] = 1;// 标注为已访问 31 // 判断是否到达终点 32 if (x == m - 1 && y == n - 1) {// 走到出口 33 System.out.println(poll.depth); 34 break; 35 } 36 // 加四个邻居 37 if (x - 1 >= 0 && vis[x - 1][y] == 0 && graph[x - 1][y] == '.') { 38 queue.add(new Node(x - 1, y, deep + 1)); 39 } 40 if (x + 1 < m && vis[x + 1][y] == 0 && graph[x + 1][y] == '.') { 41 queue.add(new Node(x + 1, y, deep + 1)); 42 } 43 if (y - 1 >= 0 && vis[x][y - 1] == 0 && graph[x][y - 1] == '.') { 44 queue.add(new Node(x, y - 1, deep + 1)); 45 } 46 if (y + 1 < n && vis[x][y + 1] == 0 && graph[x][y + 1] == '.') { 47 queue.add(new Node(x, y + 1, deep + 1)); 48 } 49 } 50 } 51 52 static class Node { 53 int x; 54 int y; 55 int depth; 56 57 public Node(int x, int y, int depth) { 58 this.x = x; 59 this.y = y; 60 this.depth = depth; 61 } 62 } 63 }
运行结果：
