rt，看了坑点，调不出来了。

#include<bits/stdc++.h>
using namespace std;
queue<int> qx, qy;
int dis[505][505], c[505][505], stx, sty, ans = 2e9;
int dx[4] = {0, 1, 0, -1};
int dy[4] = {1, 0, -1, 0};
char mp[505][505];
void bfs(){
	qx.push(stx);
	qy.push(sty);
	dis[stx][sty] = 0;
	while(qx.size()){
		int x = qx.front(), y = qy.front();
		qx.pop(); qy.pop();
		for(int i = 0; i < 4; i ++){
			int tx = x + dx[i], ty = y + dy[i];
			if(tx >= 0 && tx <= 500 && ty >= 0 && ty <= 500 && dis[tx][ty] == 2e9 && mp[tx][ty] != '#'){
				qx.push(tx);
				qy.push(ty);
				dis[tx][ty] = min(dis[x][y] + 1, dis[tx][ty]);
			}
		}
	}
}
int main(){
	int n;
	cin >> n;
	for(int i = 0; i <= 500; i ++)
		for(int j = 0; j <= 500; j ++)
		mp[i][j] = '.', c[i][j] = 2e9, dis[i][j] = 2e9;
	for(int i = 1; i <= n; i ++){
		int x, y, t;
		cin >> x >> y >> t;
		c[x][y] = min(c[x][y], t);
		c[x][y + 1] = min(c[x][y + 1], t);
		c[x][y - 1] = min(c[x][y - 1], t);
		c[x + 1][y] = min(c[x + 1][y], t);
		c[x - 1][y] = min(c[x - 1][y], t);
	}
	stx = sty = 0;
	bfs();
	dis[stx][sty] = 0;
	for(int i = 0; i <= 500; i ++)
		for(int j = 0; j <= 500; j ++){
			if(c[i][j] != 2e9){
				if(dis[i][j] >= c[i][j]) mp[i][j] = '#';
			}
			dis[i][j] = 2e9;
		}
	bfs();
	dis[stx][sty] = 0;
	for(int i = 0; i <= 500; i ++){
		for(int j = 0; j <= 500; j ++){
			if(c[i][j] == 2e9 && dis[i][j] != 2e9 && mp[i][j] != '#') ans = min(ans, dis[i][j]);
		}
	}
	if(ans != 2e9) cout << ans;
	else cout << -1;
	return 0;
}

求救，说错误点悬1关，改好悬2关。