会弹出

#error This file requires compiler and library support for the \

这个代码，望大佬解惑 代码：

#include<iostream>
#include<cstring>
#include<algorithm>
#include<unordered_map>
#include<queue>
using namespace std;
string start;
int fx[] = {0 , 1 , -1 , 0 , 0};
int fy[] = {0 , 0 , 0 , 1 , -1};
int bfs(string start){
	string end = "123804765";
	unordered_map<string , int> dist;
	queue<string> q;
	q.push(start);
	dist[start] = 0;
	while(!q.empty()){
		string k = q.front();
		int distance = dist[k];
		q.pop();
		if(k == end) return distance;
		int p = k.find('0');
		int x = p / 3 , y = p % 3;
		for(int i = 1;i <= 4;i++){
			int newx = x + fx[i];
			int newy = y + fy[i];
			if(newx >= 0 && newx < 3 && newy >= 0 && newy < 3){
				swap(k[p] , k[newx * 3 + newy]);
				if(!dist.count(k)){
					dist[k] = distance + 1;
					q.push(k);
				}
				swap(k[p] , k[newx * 3 + newy]);
			}
		}
	}
	return -1;
}
int main(){
	cin >> start;
	cout << bfs(start) << endl;
	return 0;
}