#include <bits/stdc++.h>
#define f(i,a,b) for(int i=a;i<=b;i++)
#define g(i,a,b) for(int i=a;i>=b;i--)
using namespace std;
int n,m;
char maze[305][305],ch;
struct door {
	int x1,y1,x2,y2;
}trans[100];
struct point {
	int x,y,step;
}; 
queue<point>q; 
int dx[] = {-1,1,0,0};
int dy[] = {0,0,-1,1};//方向： 上下左右  
int main(){
	cin >> n >> m;
	f(i,1,n) {
		f(j,1,m) {
			cin >> maze[i][j];
			ch=maze[i][j];
			//传送装置
			if(ch >= 'A' && ch <= 'Z') {
				if(trans[ch].x1 == 0) trans[ch].x1 = i,trans[ch].y1 = j;
				else trans[ch].x2 = i,trans[ch].y2 = j;
			}
			if(ch == '@') { //起点 
				q.push(point{i,j,0});
				maze[i][j] = '#';
			} 
		}
	}        //输入处理完毕
	while(!q.empty()) { //bfs搜索 
		point p = q.front();
		q.pop();
		f(i,0,3) {
			int ux = p.x + dx[i],uy = p.y + dy[i];
			if(ux < 1 || ux > n || uy < 1 || uy > m) continue;
			ch = maze[ux][uy];
			if(ch == '#') continue;
			if(ch == '=') {
				cout << p.step+1;
				return 0;
			}
			if(ch >= 'A' && ch <= 'Z') {
				if(ux == trans[ch].x1) ux = trans[ch].x2,uy = trans[ch].y2;
				else ux = trans[ch].x1,uy = trans[ch].y1;
				q.push(point{ux,uy,p.step+1});
				continue;
			}
			//下面是迷宫草地
			if(ch == '.') {
				q.push(point{ux,uy,p.step+1});
				//printf("ux %d uy %d step %d............\n",ux,uy,p.step+1);
				maze[ux][uy] = '#'; 
			}	
		}
		//printf("p.x=%d p.y=%d p.step=%d\n",p.x,p.y,p.step); 
	} 
    return 0;
}

第47行那里本来是 if(ux == trans[ch].x1)，这样写就错了2#，3#，4#，三个点，6#TLE了， 改成 if(ux == trans[ch].x1 && uy == trans[ch].y1) 就AC了，

百思不得其解，求大神指点。