代码略长包涵 luogu oj全ae,蓝桥vip oj可以下载输入输出样例,自己在试过,全ac,但是蓝桥vip oj也是re,New OJ也是全re, 只有蓝桥练习ac不知道什么原因

import java.io.*;
import java.util.Arrays;
import java.util.LinkedList;
import java.util.Queue;

/**
 * ClassName: 穿越雷区
 * Package:  com.搜索
 * Describe:https://www.luogu.com.cn/problem/P8628
 *
 * @Create 2023/03/30 11:34
 */
public class Main {
    static int n,ans = Integer.MAX_VALUE;static char[][] map;static int[][] vis;static Pos A,B; static int[][] steps ;
    static int ts = 0;
    public static void main(String[] args) throws Exception {

        // 输入
        n = nextInt(); map = new char[n][n]; vis = new int[n][n];steps = new int[n][n];
        for(int i = 0; i < n; i++){
            String row = bf.readLine();
            for(int j = 0,k = 0;  k < n; j++){
                char c = row.charAt(j);if(c == ' ')continue;
                map[i][k] = row.charAt(j); if(map[i][k] == 'A') A = new Pos(i,k);   if(map[i][k] == 'B') B = new Pos(i,k);k++;
            }
        }
        // 从A点出发两种路径                                                              清空状态走第二种
        bfs(A,1);vis = new int[n][n];steps = new int[n][n]; queue = new LinkedList<>(); bfs(A,2);
        pw.println(ans - 1);pw.flush();
    }
    static class Pos{int y,x; public Pos(int y,int x){this.y = y; this.x = x;} }
    static Queue<Pos> queue = new LinkedList<>(); static int[][] di = { {1,0} ,{ 0,1} ,{-1, 0} ,{0,-1} };
    static void bfs(Pos A,int sta){
        queue.add(A); steps[A.y][A.x] = 1; vis[A.y][A.x] = sta;
        while(!queue.isEmpty()){
            Pos cur = queue.poll(); int y = cur.y,x = cur.x,ny,nx;  int step = steps[y][x];

            // 匹配到B
            if(map[y][x] == 'B'){
                ans = Math.min(ans,step); return;
            }

            // 确定该点可以进入的状态    如果是A点,状态不改
            if(cur != A){   //状态为 '-' 只能配置1'+'号  ,否则就是2'-'
                vis[y][x] = map[y][x] == '-' ? 1 : 2;
            }

            for(int i = 0; i < 4; i++){
                ny = y + di[i][0]; nx = x + di[i][1];
                if(check(ny,nx,vis[y][x])){
                    queue.add(new Pos(ny,nx)); steps[ny][nx] = step + 1;
                }
            }
        }
    }

    static boolean check(int y,int x,int sta){  //'0' 表示未访问 1表示 只能匹配'+'  ,2 表示只能匹配'-'

        char[] status = {0,'+','-' };
        // 保证该点没有越界                              保证该点状态对应                该点是'B             未访问过
        return y >= 0 && y < n && x >= 0 && x < n && (map[y][x] == status[sta] || map[y][x] == 'B') && steps[y][x] == 0;
    }


    static BufferedReader bf = new BufferedReader(new InputStreamReader(System.in));
    static StreamTokenizer st = new StreamTokenizer(bf);
    static int nextInt()throws Exception{st.nextToken(); return (int)st.nval;}
    static PrintWriter pw = new PrintWriter(new OutputStreamWriter(System.out));
}