prim算法+优化 模版

#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[30],next[200],point[200],val[200],size,dist[30];    //前向星及dist数组bool vis[30];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=0;    memset(dist,-1,sizeof(dist));    memset(vis,0,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]=0;    vis[s]=1;    while(!q.empty()){        pii u=q.top();        q.pop();        if(vis[u.second])continue;        vis[u.second]=1;        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]==-1)){                dist[j]=val[i];                q.push(make_pair(dist[j],j));            }        }    }    printf("%d\n",ans);}

prim算法优化