算法1

BFS

Java 代码

import java.io.*;
import java.util.*;

class Main{
    static int n, m;
    static int[][] grid;
    public static void main(String[] args) throws Exception{
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        String[] s1 = br.readLine().split("\\s+");
        n = Integer.valueOf(s1[0]);
        m = Integer.valueOf(s1[1]);

        int[][] dirs = {{1,0}, {-1, 0}, {0, -1}, {0, 1}};
        Queue<int[]> q = new LinkedList<>();
        int[][] d = new int[n][m]; 
        grid = new int[n][m];
        //迷宫grid
        for(int i = 0; i < n; i++) {
            String[] s = br.readLine().split("\\s+");
            for (int j = 0; j < m; j++) {
                grid[i][j] = Integer.parseInt(s[j]);
            }
        }

        q.add(new int[]{0, 0});
        while(!q.isEmpty()){
            int[] node = q.poll();
            for(int[] dir: dirs){
                int x = node[0] + dir[0];
                int y = node[1] + dir[1];
                if(isValid(x, y, grid, d)){
                    q.add(new int[]{x, y});
                    d[x][y] = d[node[0]][node[1]] + 1;
                }
            }
        }
        System.out.print(d[n-1][m-1]);
    }

    private static boolean isValid(int x, int y, int[][] grid, int[][] d){
        return x >= 0 && x < grid.length && y >= 0 && y < m && grid[x][y] == 0 && d[x][y] == 0;
    }
}