UVa 821 Page Hopping【Floyd】

 1 #include<iostream>  
 2 #include<cstdio>  
 3 #include<cstring> 
 4 #include <cmath> 
 5 #include<stack>
 6 #include<vector>
 7 #include<map> 
 8 #include<set>
 9 #include<queue> 
10 #include<algorithm>  
11 using namespace std;
12 
13 typedef long long LL;
14 const int INF = (1<<30)-1;
15 const int mod=1000000007;
16 const int maxn=1005;
17 int d[maxn][maxn];
18 
19 int main(){
20     int n,m,u,v,ans,kase=0;
21     while(scanf("%d %d",&u,&v)!=EOF){
22         memset(d,0,sizeof(d));
23         if(u==0&&v==0) break;        
24                 
25          for(int i=1;i<=105;i++){
26             for(int j=1;j<=105;j++){
27                 if(i==j) d[i][j]=0;
28                 else d[i][j]=INF;
29             }            
30         }
31         n=max(u,v);d[u][v]=1;
32         while(scanf("%d %d",&u,&v)!=EOF){
33             if(u==0&&v==0) break;
34             n=max(max(u,v),n);
35             d[u][v]=1;
36         }
37         
38         for(int k=1;k<=n;k++)
39          for(int i=1;i<=n;i++)
40           for(int j=1;j<=n;j++)
41           if(d[i][k]<INF&&d[k][j]<INF)
42            d[i][j]=min(d[i][j],d[i][k]+d[k][j]);
43            
44            int sum=0,cnt=0;
45     
46            for(int i=1;i<=n;i++)
47             for(int j=1;j<=n;j++)
48                 if(d[i][j]!=INF&&d[i][j]!=0) sum+=d[i][j],cnt++;
49 
50             double tmp=1.0*sum/cnt;
51              printf("Case %d: average length between pages = %.3lf clicks\n",++kase,tmp);        
52     }
53     return 0;
54 }