题解

刚考完，拿来测一下
输了，当时没有return-1

#include <iostream>
#include <cstdio>
#include <vector>
#include <queue>
using namespace std;
struct node{
	int x, y, step;
};
char mp[505][505];
bool vis[505][505];
int dir[4][2] = {-1, 0, 0, -1, 0, 1, 1, 0};
vector <node> v;//记录传送门
int n, m, x1, y1;
bool check(int x, int y){
	if(x < 1 || x > n || y < 1 || y > m) return 0;
	if(mp[x][y] == '#' || vis[x][y]) return 0;
	return 1;
}
int bfs(){
	queue <node> q;
	q.push({1, 1, 1});
	while(!q.empty()){
		node head = q.front();
		q.pop();
		if(head.x == n && head.y == m) return head.step;//到右下角就停
		for(int i = 0; i < 4; i++){
			int xx = head.x + dir[i][0], yy = head.y + dir[i][1];
			if(check(xx, yy)){
				if(mp[xx][yy] == '$'){//到传送门了
					for(int j = 0; j < v.size(); j++){
						if(!vis[v[j].x][v[j].y]) vis[v[j].x][v[j].y] = 1, q.push({v[j].x, v[j].y, head.step + 1});
					}
				}else{
                    vis[xx][yy] = 1;
				    q.push({xx, yy, head.step + 1});//正常走
                }
			}
		}
	}return -1;
}
int main(){
	cin >> n >> m;
	for(int i = 1; i <= n; i++){
		for(int j = 1; j <= m; j++){
			cin >> mp[i][j];
			if(mp[i][j] == '$') v.push_back({i, j, 0}); 
		}
	}cout << bfs();

	return 0;
}