1 #include <cstdio> 2 #include <algorithm> 3 #include <cstring> 4 using namespace std; 5  6 const int maxn = 100 + 5; 7 const int INF = 100000001; 8  9 int d[maxn][maxn];10 11 int main() {12     int u, v, kase = 0;13     while (scanf("%d%d", &u, &v) == 2 && (u || v)) {14         for (int i = 0; i < maxn; i++)15             for (int j = 0; j < maxn; j++) d[i][j] = INF;16         for (int i = 0; i < maxn; i++) d[i][i] = 0;17         int n = 0; n = max(n, max(u, v));18         d[u][v] = 1;19         while (scanf("%d%d", &u, &v) && (u || v)) { n = max(n, max(u, v)); d[u][v] = 1; }20         for (int k = 1; k <= n; k++)21             for (int i = 1; i <= n; i++)22                 for (int j = 1; j <= n; j++)23                     d[i][j] = min(d[i][j], d[i][k] + d[k][j]);24         int sum = 0, cnt = 0;25         for (int i = 1; i <= n; i++)26             for (int j = 1; j <= n; j++)27                 if (d[i][j] < INF && d[i][j])28                     sum += d[i][j], cnt++;29         printf("Case %d: average length between pages = %.3lf clicks\n", ++kase, 1.0 * sum / cnt);30     }31     return 0;32 }