照着书上查了好几遍了，还是没有找出bug在何方

求大佬帮我看看

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

typedef pair<int,int> pii;
bool operator<(const pii &a,const pii &b)
{
	return a.first>b.first;
} 

priority_queue<pii> q;

const int maxn=200000+5;
int n,m,s,tot;
int head[maxn],ver[maxn],edge[maxn],Next[maxn];
long long d[maxn];
bool v[maxn];

void add(int x,int y,int z)
{
	ver[++tot]=y,edge[tot]=z;
	Next[tot]=head[x],head[x]=tot;
}

int main()
{
	scanf("%d%d%d",&n,&m,&s);
	
	for(int i=1;i<=m;++i)
	{
		int u,v,w;
		scanf("%d%d%d",&u,&v,&w);
		
		add(u,v,w);
	}
	
	//memset(d,0x3f,sizeof(d));
	for(int i=1;i<=n;++i)d[i]=1e10;
	memset(v,0,sizeof(v));
	d[s]=0;
	
	q.push(make_pair(0,s));
	
	while(q.size())
	{	
		int x=q.top().second;
		q.pop();
		if(v[x])continue;
		v[x]=1;
		
		for(int i=head[x];i;i=Next[i])
		{
			int y=ver[i],z=edge[i];
			if(d[y]>(long long)d[x]+z)
			{
				d[y]=d[x]+z;
				q.push(make_pair(d[y],y));	
			}
		}
	}
	
	for(int i=1;i<=n;++i)printf("%lld ",d[i]);
	return 0;
}