求助，WA了最后四个点,数据量太大，测不出来

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

typedef pair<int,int> PII;
int m,t[1010],step[310][310];
PII star[50010];
queue<PII> q;

int dx[] = {0,0,-1,1};
int dy[] = {1,-1,0,0};

bool checkMove(int x,int y,int curTime)//检查是否可以移动到(x,y),curTime为当前时刻 
{
    if(x < 0 || y < 0 || step[x][y] != -1) return false;
    for(int i = 1;i <= m;i++)
    {
        if(abs(x - star[i].first) <= 1 && y == star[i].second && curTime >= t[i]) return false;
        if(abs(y - star[i].second) <= 1 && x == star[i].first && curTime >= t[i]) return false;
    }
    return true;
}

bool checkSec(int x,int y)//检查是否安全 
{
    for(int i = 1;i <= m;i++)
    {
        if(abs(x - star[i].first) <= 1 && y == star[i].second) return false;
        if(abs(y - star[i].second) <= 1 && x == star[i].first) return false;
    }
    return true;
}

int main()
{
    cin >> m;
    for(int i = 1;i <= m;i++)
    {
        cin >> star[i].first >> star[i].second >> t[i];
    }
    //bfs
    memset(step,-1,sizeof(step));
    q.push({0,0});
    step[0][0] = 0;
    while(!q.empty())
    {
        PII b = q.front();
        q.pop();
        for(int i = 0;i < 4;i++)
        {
            PII a = b;
            a.first += dx[i];
            a.second += dy[i];
            if(checkMove(a.first,a.second,step[b.first][b.second] + 1))
            {
                q.push(a);
                step[a.first][a.second] = step[b.first][b.second] + 1;
                if(checkSec(a.first,a.second))
                {
                    cout << step[a.first][a.second];
                    return 0;
                }
            }
        }
    }
    cout << "-1";
    return 0;
}