66行爆搜TLE求调

#include<bits/stdc++.h>
using namespace std;
const int N=50010,M=310;
int n,x[N],y[N],t[N],ans=1e9,mp[M][M];
bool vis[M][M];
struct node{int x,y,t;}a[N];
queue<node>q;
bool cmp(node a,node b){return a.t<b.t;}
const int dx[]={0,0,1,-1};
const int dy[]={1,-1,0,0};
bool check(int x,int y){
    if(x<1||x>M+1||y<1||y>M+1||vis[x][y]||mp[x][y]==1)return 0;
    else return 1;
}
int bfs(int nx,int ny){
    memset(vis,0,sizeof(vis));
    for(int i=1;i<=M+1;++i){
        for(int j=1;j<=M+1;++j){
            if(mp[i][j]==1)mp[i][j]=0;
        }
    }
    while(q.size())q.pop();
    q.push({0,0,0});
    while(q.size()){
        node now=q.front();
        q.pop();
        for(int i=0;i<4;++i){
            int xx=dx[i]+now.x;
            int yy=dy[i]+now.y;
            int l=0,r=n,mid;
            while(l<=r){
                mid=l+r>>1;
                if(a[mid].t<now.t+1)l=mid+1;
                else r=mid-1;
            }
            if(a[r].t==now.t+1){
                mp[a[r].x][a[r].y]=1;
                mp[a[r].x+1][a[r].y]=1;
                mp[a[r].x-1][a[r].y]=1;
                mp[a[r].x][a[r].y+1]=1;
                mp[a[r].x][a[r].y-1]=1;
            }
            if(!check(xx,yy))continue;
            q.push({xx,yy,now.t+1});
            vis[xx][yy]=1;
            if(xx==nx&&yy==ny)return now.t+1;
        }
    }
    return 1e9;
}
int main(){
    cin>>n;
    for(int i=1;i<=n;++i){
        scanf("%d%d%d",&a[i].x,&a[i].y,&a[i].t);
        mp[a[i].x][a[i].y]=2;
    }
    sort(a+1,a+1+n,cmp);
    for(int i=1;i<=M+1;++i){
        for(int j=1;j<=M+1;++j){
            if(mp[i][j]!=2)ans=min(ans,bfs(i,j));
        }
    }
    if(ans==1e9)cout<<-1;
    cout<<ans;
    return 0;
}