hdu 1162 Eddy's picture

http://acm.hdu.edu.cn/showproblem.php?pid=1162

 1 #include <cstdio>
 2 #include <cstring>
 3 #include <iostream>
 4 #include <cmath>
 5 #include <algorithm>
 6 #define maxn 200
 7 using namespace std;
 8 const int inf=1<<30;
 9 
10 double g[maxn][maxn];
11 int n;
12 bool vis[maxn];
13 double dist[maxn];
14 double sum;
15 struct node
16 {
17     double x,y;
18 }p[maxn];
19 
20 double sqr(double x)
21 {
22     return x*x;
23 }
24 
25 double dis(int x1,int y1,int x2,int y2)
26 {
27     return sqrt(sqr(x1-x2)+sqr(y1-y2));
28 }
29 
30 void prim()
31 {
32     memset(vis,false,sizeof(vis));
33     for(int i=1; i<=n; i++) dist[i]=g[1][i];
34     dist[1]=0;
35     vis[1]=true;
36     for(int i=1; i<n; i++)
37     {
38         double m=(double)inf;
39         int x;
40         for(int j=1; j<=n; j++) if(!vis[j]&&dist[j]<m) m=dist[x=j];
41         sum+=m;
42         vis[x]=true;
43         for(int j=1; j<=n; j++) if(!vis[j]) dist[j]=min(dist[j],g[x][j]);
44     }
45 }
46 
47 
48 int main()
49 {
50     while(scanf("%d",&n)!=EOF)
51     {
52         for(int i=1; i<=n; i++)
53         {
54             cin>>p[i].x>>p[i].y;
55         }
56         for(int i=1; i<=n; i++)
57         {
58             for(int j=1; j<=n; j++)
59             {
60                 double d=dis(p[i].x,p[i].y,p[j].x,p[j].y);
61                 g[i][j]=g[j][i]=d;
62             }
63         }
64         sum=0;
65         prim();
66         printf("%.2lf\n",sum);
67     }
68     return 0;
69 }
View Code

 

posted @ 2014-04-13 20:26  null1019  阅读(110)  评论(0)  编辑  收藏  举报