UVA821 PageHopping （Floyd）

#include<bits/stdc++.h>
using namespace std;

const int maxn = 101;

int g[maxn][maxn];
bool vis[maxn];
vector<int> p;
const int INF = 0x3f3f3f3f;

int main()
{
//freopen("in.txt","r",stdin);
int u,v,kas = 0;
memset(g,0x3f,sizeof(g));
for(int i = 1; i < maxn; i++) g[i][i] = 0;
while(scanf("%d%d",&u,&v),u){
p.clear(); memset(vis,0,sizeof(vis));
g[u][v] = 1; vis[u] = vis[v] = true;
while(scanf("%d%d",&u,&v),u){
g[u][v] = 1;
vis[u] = vis[v] = true;
}
for(int i = 1; i < maxn; i++){
if(vis[i]) p.push_back(i);
}
int sz = p.size();

for(int k = 0; k < sz; k++){
int m = p[k];
for(int i = 0; i < sz; i++){
int u = p[i];
if(g[u][m]<INF){
for(int j = 0; j < sz; j++){
int v = p[j];
g[u][v] = min(g[u][v],g[u][m]+g[m][v]);
}
}
}
}

int sum = 0;
for(int i = 0; i < sz; i++){
int u = p[i];
for(int j = 0; j < sz; j++) if(i!=j){
int v = p[j];
sum += g[u][v];
g[u][v] = INF;
}
}
printf("Case %d: average length between pages = %.3lf clicks\n",++kas,(double)sum/(sz*(sz-1)));
}
return 0;
}