求助，为什么会RE啊，数组大小也合适啊

#include <bits/stdc++.h>
using namespace std;

#define f first
#define s second
const int N = 310;
typedef pair<int,int> PII;
queue<PII> q;
int g[N][N],dist[N][N];
int m;
vector<PII> v(50010);
int T[1010];
int dx[]={-1,0,1,0}, dy[]={0,1,0,-1};

void fun(PII p, int weight){
    int x=p.f, y=p.s;
    g[x][y] = min(weight,g[x][y]);
    for(int i=0; i<4; i++){
        int a=x+dx[i], b=y+dy[i];
        if(a<0 || b<0 || a>301 || b>301) continue;
        g[a][b] = min(weight,g[a][b]);
    }
}

int bfs(int x, int y){
    q.push({x,y});
    dist[x][y] = 0;
    while(!q.empty()){
        auto t =q.front();
        q.pop();
        for(int i=0; i<4; i++){
            int a=t.f+dx[i], b=t.s+dy[i];
            if(a<0 || b<0) continue;
            if(dist[a][b]!=0) continue;
            dist[a][b] = dist[t.f][t.s]+1;
            if(dist[a][b] >= g[a][b]) continue;
            q.push({a,b});
            if(g[a][b] > 1e9) return dist[a][b];
        }
    }
    return -1;
}

int main()
{
    cin>>m;
    int x,y,ti;
    memset(g,0x3f,sizeof(g));
    for(int i=0; i<m; i++){
        scanf("%d%d%d",&x,&y,&ti);
        v[i]={x,y};
        T[i] = ti;
    }
    for(int i=0; i<m; i++){//预处理出流星矩阵
        fun(v[i],T[i]);
    }
    cout<<bfs(0,0);
    return 0;
}