[51nod p2673] shortest path [heap optimization Dijk]

$link$

analysis ：

Does this chip data really need heap optimization $floyed$ Can pass

CODE：

#include<iostream>
#include<cstdio>
#include<algorithm>
#include<cstring>
#include<queue>
#define reg register
using namespace std;
typedef long long ll;
const int N=5e4+5;
int n,m,s,t,tot;
int head[N],vis[505];
ll dis[505];
struct Edge{
    
	int to,next,k;
}a[N<<1];
void add(int x,int y,int k)
{
    
	a[++tot]=(Edge){
    y,head[x],k};
	head[x]=tot;
}
priority_queue<pair<int,int>,vector<pair<int,int> >,greater<pair<int,int> > > q;
void Dijkstra(int st)
{
    
	memset(dis,0x7f,sizeof dis);
	dis[st]=0;
	q.push(make_pair(0,st));
	while(!q.empty())
	{
    
		int x=q.top().second;
		q.pop();
		if(vis[x]) continue;
		vis[x]=1;
		for(int i=head[x];i;i=a[i].next)
		{
    
			int qwq=a[i].to;
			if(dis[qwq]>dis[x]+a[i].k)
			{
    
				dis[qwq]=dis[x]+a[i].k;
				if(!vis[qwq])
					q.push(make_pair(dis[qwq],qwq));
			}
		}
	}
}
int main(){
    
	scanf("%d%d",&n,&m);
	for(int i=1,x,y,w;i<=m;i++)
	{
    
		scanf("%d%d%d",&x,&y,&w);
		add(x,y,w);
		add(y,x,w);
	}
	scanf("%d%d",&s,&t);
	Dijkstra(s);
	printf("%lld",dis[t]);
	return 0;
}