最小生成树prim+邻接表优化

#include   
#include    
#include  
#include  
using namespace std;  
const int inf=0x3f3f3f3f;;
const int maxx=1e3+100;;
const int maxn=2e6+10;
typedef long long ll;
int m,n,q,ans,sum;  
int dis[maxx];
int sto[maxx];
int head[2*maxn];
bool vis[maxx]; 
int a[maxx][maxx];
struct  point{    
    int to;  
    int next; 
	int val; 
	bool operator < (const point &a) const
	{
		return val>a.val;
	}
};  
point pt[2*maxn]; 
void add(int u,int v,int val)
{
	      pt[q].next=head[u];  
          pt[q].to=v;
		  pt[q].val=val;
		  head[u]=q++;
} 
void prim(int st)  
{  
    priority_queueq;
    point t1,t2;
	int w,v;
    memset(dis,inf,sizeof(dis));
    memset(vis,false,sizeof(vis));
    for (int i=head[st];i!=-1;i=pt[i].next)
    {
    	 int v=pt[i].val;
    	 if (dis[pt[i].to]>v)
    	 {
    	 	dis[pt[i].to]=v;
    	 	t1.to=pt[i].to;
    	 	t1.val=v;
    	 	q.push(t1);
		 }
	}
	vis[st]=true;
	ans=1;sum=0;
	while (!q.empty())
	{
		point t=q.top();
		q.pop();
		int v=t.to;
		if (vis[v])continue;
		vis[v]=true;
		sum+=dis[v];
		ans++;
		for (int i=head[v];i!=-1;i=pt[i].next)
		{
			 int u=pt[i].to;
			 if (!vis[u]&&pt[i].val>m>>n>>k;
	memset(head,-1,sizeof(head));
	q=1;
	for (int i=0;i>u>>v>>val;
		add(u,v,val);
		add(v,u,val);
		st=u;
	}
    prim(st); 
    if (ans==n)
    cout<