• 下面的代码哪里不对呢？
• 试一试这组数据

4 4
#.##
#A##
##A@
##=#

• 下面的代码会输出什么答案呢？

#include <bits/stdc++.h>
using namespace std;
int n , m , sx = -1 , sy = -1 , ex = -1 , ey = -1 , dis[305][305] , tx[26][2] , ty[26][2] , tcnt[26];
char a[305][305];
const int dx[] = {-1 , 0 , 0 , 1} , dy[] = {0 , -1 , 1 , 0};
void bfs(){
	memset(dis , -1 , sizeof(dis));
	queue<int> qx , qy;
	dis[sx][sy] = 0;
	qx.push(sx) , qy.push(sy);
	while(!qx.empty()){
		int x = qx.front() , y = qy.front();
		qx.pop() , qy.pop();
		if(x == ex && y == ey) return;
		if(a[x][y] >= 'A' && a[x][y] <= 'Z'){
			int t = a[x][y] - 'A' , nx , ny;
			if(tx[t][0] == x && ty[t][0] == y) nx = tx[t][1] , ny = ty[t][1];
			else nx = tx[t][0] , ny = ty[t][0];
			if(dis[nx][ny] == -1){
				dis[nx][ny] = dis[x][y];
				qx.push(nx) , qy.push(ny);
				x = nx , y = ny;
			}
		}
		for(int i = 0 ; i < 4 ; i++){
			int nx = x + dx[i] ,  ny = y + dy[i];
			if(nx >= 0 && nx < n && ny >= 0 && ny < m && a[nx][ny] != '#'){
				if(dis[nx][ny] == -1){
					dis[nx][ny] = dis[x][y] + 1;
					qx.push(nx) , qy.push(ny);
				}
			}
		}
	}
}
int main(){
	cin >> n >> m;
	for(int i = 0 ; i < n ; i++){
		for(int j = 0 ;j < m ; j++){
			cin >> a[i][j];
			if(a[i][j] == '@') sx = i , sy = j;
			else if(a[i][j] == '=') ex = i , ey = j;
			else if(a[i][j] >= 'A' && a[i][j] <= 'Z'){
				int x = a[i][j] - 'A';
				tx[x][tcnt[x]] = i , ty[x][tcnt[x]] = j;
				tcnt[x]++;
			}
		}
	}
	bfs();
	cout << dis[ex][ey];
}