[HAOI2006]聪明的猴子

 
/*
找出能连通所有点的一棵树 是的最大的边最小
很显然就是最小生成树. 堆优化prim.
*/
#include<iostream>
#include<cstring>
#include<cstdio>
#include<cmath>
#include<queue> 
#define maxn 1010
#define inf 999999999
using namespace std;
int n,m,num,head[maxn],ans,tot;
bool f[maxn];
double x[maxn],y[maxn],v[maxn],dis[maxn],maxx;
struct edge
{
    int u,v,pre;
    double t;
}e[maxn*maxn];
struct node
{
    int ki,si;
    node (int kk,int ss):ki(kk),si(ss) {};
    bool operator < (const node & a) const
      {
        return si>a.si;
      }
};
priority_queue<node>q;
double Get_dis(int a,int b,int c,int d)
{
    return sqrt((a-c)*(a-c)+(b-d)*(b-d));
}
double min(double a,double b)
{
    return a>b?a:b;
}
void Add(int from,int to,double dis)
{
    num++;e[num].u=from;e[num].v=to;e[num].t=dis;
    e[num].pre=head[from];head[from]=num;
}
void Prim()
{
    for(int i=0;i<=n;i++)dis[i]=inf;
    q.push(node(1,0));dis[1]=0;
    while(!q.empty()&&tot<n)
      {
        int k=q.top().ki;q.pop();
        if(f[k])continue;f[k]=1;
        maxx=max(maxx,dis[k]);tot++;
        for(int i=head[k];i;i=e[i].pre)
          {
            int v=e[i].v;
            if(dis[v]>e[i].t)
              {
                dis[v]=e[i].t;
                q.push(node(v,dis[v]));
              }
          }
      }
}
int main()
{
    scanf("%d",&m);
    for(int i=1;i<=m;i++)
      scanf("%lf",&v[i]);
    scanf("%d",&n);
    for(int i=1;i<=n;i++)
      scanf("%lf%lf",&x[i],&y[i]);
    for(int i=1;i<=n;i++)
      for(int j=1;j<=n;j++)
        {
          if(i==j)continue;
          double tmp=double(Get_dis(x[i],y[i],x[j],y[j]));
          Add(i,j,tmp);
        }
    Prim();
    for(int i=1;i<=m;i++)
      if(v[i]>=maxx)
        ans++;
    printf("%d
",ans);
    return 0;
}