bfs模板

#include <bits/stdc++.h>
using namespace std;
char mp[35][55];
int dx[4] = {1, -1, 0, 0};
int dy[4] = {0, 0, -1, 1};
int vis[35][55] = {0};
struct node{
	int x, y, step;
	bool friend operator < (node a,node b){
		return a.step > b.step;
	}
};
priority_queue<node>que;
int bfs(){
	node st = {0, 0, 0};
	que.push(st);
	while(que.size()){
		node cur = que.top();
		cout<<cur.step<<endl;
		if(cur.x == 29 && cur.y == 49) return cur.step;
		que.pop();
		for(int i = 0; i < 4; i++){
			int xx = cur.x + dx[i];
			int yy = cur.y + dy[i];
			if(xx < 0 || xx >= 30 || yy < 0 || yy >= 50 || mp[xx][yy] == '1' || vis[xx][yy]) continue;
			vis[xx][yy] = 1;
			node tmp = {xx, yy, cur.step + 1};
			que.push(tmp);
		}
	}
	return -1;
}
int main(){
	for(int i = 0; i < 30; i++){
		for(int j = 0; j < 50; j++){
			cin>>mp[i][j];
		}
	}
	cout<<bfs()<<endl;
	return 0;
}