最小生成树--prim+优先队列优化模板

prim+优先队列模板：

 #include<stdio.h>    //大概要这些头文件
 #include<string.h>
 #include<queue>
 #include<vector>
 #include<algorithm>
 using namespace std;
 typedef pair<int,int> pii;

 int head[],next[],point[],val[],size,dist[];    //前向星及dist数组
 bool vis[];

 void add (int a,int b, int v){    //加边及去重
     int i;
     for(i=head[a];~i;i=next[i]){
         if(point[i]==b){
             if(val[i]>v)val[i]=v;
             return;
         }
     }
     point[size]=b;
     val[size]=v;
     next[size]=head[a];
     head[a]=size++;
 }

 struct cmp{    //重载小根堆
     bool operator()(pii a,pii b){
         return a.first>b.first;
     }
 };

 void prim(int s){    //prim函数，传入图中一点
     int i,ans=;
     memset(dist,-,sizeof(dist));
     memset(vis,,sizeof(vis));
     priority_queue<pii,vector<pii>,cmp>q;
     for (i=head[s];~i;i=next[i]){
         dist[point[i]]=val[i];
         q.push(make_pair(dist[point[i]],point[i]));
     }
     dist[s]=;
     vis[s]=;
     while(!q.empty()){
         pii u=q.top();
         q.pop();
         if(vis[u.second])continue;
         vis[u.second]=;
         ans+=u.first;
         for(i=head[u.second];~i;i=next[i]){
             int j=point[i];
             if(!vis[j]&&(dist[j]>val[i]||dist[j]==-)){
                 dist[j]=val[i];
                 q.push(make_pair(dist[j],j));
             }
         }
     }
     printf("%d\n",ans);
 }