AcWing 1101.献给阿尔吉侬的花(java版)

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

public class Main
{
    static int T,n,m;   //T组数据,每组数据是n行m列
    
    static int[] dx = {-1,0,1,0};
    static int[] dy = {0,1,0,-1};   //存储偏移量,用于广度优先搜索
    
    static final int N = 210;   //数据范围
    
    static char[][] g = new char[N][N]; //用于存储每组数据的值
    static int[][] dist = new int[N][N];    //用来表示从起点到dist[i][j]的距离
    
    static BufferedReader in = new BufferedReader(new InputStreamReader(System.in));
    
    public static int bfs(PII start)
    {
        //创建一个队列,进行广度优先搜索
        Queue q = new LinkedList();
        //先将start放入,再取出,再更新start周围的dist,
        //将满足start周围四个数的地点放入队列中,再将这些书重复start的操作
        
        q.offer(start);
        
        //将数组默认赋值为-1
        for(int i = 0;i < N;i ++)
            for(int j = 0;j < N;j ++)
            {
                dist[i][j] = -1;
            }
            //起点为0
        dist[start.x][start.y] = 0;
        while(!q.isEmpty())
        {
            PII t = q.poll();   //每次都拿队头,对队头上下左右满足条件的地点更改dist
            for(int i = 0;i < 4;i ++)
            {
                int x = t.x + dx[i];
                int y = t.y + dy[i];
                if(x < 0 || x >= n || y < 0 || y >= m) continue;
                if(g[x][y] == '#') continue;    //不需要管墙壁
                if(dist[x][y] != -1) continue; //没遍历过才需要更改dist,
                                            //第一次遍历到就是最小距离,不需要更改
                dist[x][y] = dist[t.x][t.y] + 1;    //将队头周围满足条件的左边更新
                
                if(g[x][y] == 'E') return dist[x][y];   //找到元素后就可以结束循环
                
                //一轮操作后,将队头取出后记得把它周围的点放入尾部
                //周围的点也要重复队头的操作
                q.offer(new PII(x,y));
            }
        }
        return -1;
    }
    
    
    public static void main(String[] args) throws IOException
    {
        T = Integer.parseInt(in.readLine());
        while(T -- > 0)
        {
            String[] init = in.readLine().split(" ");
            n = Integer.parseInt(init[0]);
            m = Integer.parseInt(init[1]);
            
            PII start = null;
            for(int i = 0;i < n;i ++)
            {
                g[i] = in.readLine().toCharArray();
                for(int j = 0;j < m;j ++)
                {
                    if(g[i][j] == 'S')
                    start = new PII(i,j);
                }
            }
            int res = bfs(start);
            if(res == -1) System.out.println("oop!");
            else System.out.println(res);
        }
        in.close();
    }

}
class PII
{
    int x;
    int y;
    public PII(int x,int y)
    {
        this.x = x;
        this.y = y;
    }
}