HDU 1875 畅通工程再续

 1 #include <iostream>
 2 #include <cstring>
 3 #include <cstdio>
 4 #include <algorithm>
 5 #include <cmath>
 6 using namespace std;
 7 
 8 const int maxn=105;
 9 
10 int x[maxn],y[maxn];
11 int v[maxn*maxn],u[maxn*maxn];
12 double w[maxn*maxn];
13 int fa[maxn];
14 int r[maxn*maxn];
15 
16 bool cmp (int x,int y){
17     return w[x]<w[y];
18 }
19 
20 int find (int x){
21     if (fa[x]==x)
22         return x;
23     return fa[x]=find (fa[x]);
24 }
25 
26 int main (){
27     int t;
28     scanf ("%d",&t);
29     int n;
30     while (t--){
31         scanf ("%d",&n);
32         for (int i=0;i<n;i++){
33             scanf ("%d%d",&x[i],&y[i]);
34         }
35         int tot=0;
36         for (int i=0;i<n;i++){
37             for (int j=i+1;j<n;j++){
38                 int s=(x[i]-x[j])*(x[i]-x[j])+(y[i]-y[j])*(y[i]-y[j]);
39                 if (s>=100&&s<=1000000){
40                     v[tot]=i;
41                     u[tot]=j;
42                     w[tot++]=100*sqrt (s*1.0);
43                 }
44             }
45             fa[i]=i;
46         }
47         for (int i=0;i<tot;i++)
48             r[i]=i;
49         int temp=0;
50         sort (r,r+tot,cmp);
51         double ans=0;
52         for (int i=0;i<tot;i++){
53             int fv=find(v[r[i]]);
54             int fu=find(u[r[i]]);
55             if (fv!=fu){
56                 ans+=w[r[i]];
57                 temp++;
58                 fa[fv]=fu;
59             }
60         }
61         if (temp==n-1)
62             printf ("%.1f\n",ans);
63         else printf ("oh!\n");
64     }
65     return 0;
66 }