[HAOI2006]聪明的猴子

 1 #include <cstdio>
 2 #include <cmath>
 3 #include <algorithm>
 4 using namespace std;
 5 int n,m,d,cnt,ans;
 6 int x[1005],y[1005],fa[1005],monkey[1005];
 7 struct Node{
 8     int x;
 9     int y;
10     double dis;
11 }a[1000005];
12 inline int Find(int i){
13     if(fa[i]==i)return i;
14     return fa[i]=Find(fa[i]);
15 }
16 inline void Union(int x,int y){
17     int f1=Find(x);
18     int f2=Find(y);
19     if(f1!=f2)fa[f1]=f2;
20     return;
21 }
22 inline bool cmp(Node a,Node b){
23     if(a.dis==b.dis)return a.x<b.x;
24     return a.dis<b.dis;
25 }
26 int main(){
27     scanf("%d",&m);
28     for(register int i=1;i<=m;i++)
29         scanf("%d",&monkey[i]);
30     scanf("%d",&n);
31     for(register int i=1;i<=n;i++)
32         fa[i]=i;
33     for(register int i=1;i<=n;i++)
34         scanf("%d%d",&x[i],&y[i]);
35     for(register int i=1;i<=n;i++)
36         for(register int j=i+1;j<=n;j++){
37             a[++cnt].x=i;
38             a[cnt].y=j;
39             a[cnt].dis=(double)sqrt((double)(x[i]-x[j])*(double)(x[i]-x[j])+(double)(y[i]-y[j])*(double)(y[i]-y[j]));
40         }
41     sort(a+1,a+cnt+1,cmp);
42     for(register int i=1;i<=cnt;i++){
43         if(Find(a[i].x)!=Find(a[i].y)){
44             Union(a[i].x,a[i].y);
45             d=a[i].dis;
46         }
47     }
48     for(register int i=1;i<=m;i++)
49         if(monkey[i]>=d)ans++;
50     printf("%d\n",ans);
51     return 0;
52 }