Page Hopping UVA - 821

 

Floyd的模板题

#define INF 1e8
#include<cstdio>
#include<cstring>
#include<iostream>
#include<algorithm>
using namespace std;

const int maxn=10005;

int kase,cnt,sum;
int d[105][105];

void Init(){
    cnt=0,sum=0;
    for(int i=1;i<=101;i++)
        for(int j=1;j<=101;j++) d[i][j]=INF;
}

void Floyd(){
    for(int k=1;k<=100;k++){
        for(int i=1;i<=100;i++){
            for(int j=1;j<=100;j++){
                if(d[i][k]==INF||d[k][j]==INF) continue;
                d[i][j]=min(d[i][j],d[i][k]+d[k][j]);
            }
        }
    }
}

void solve(){
    Floyd();
    for(int i=1;i<=100;i++){
        for(int j=1;j<=100;j++){
            if(i==j||d[i][j]==INF) continue;
            sum=sum+d[i][j];
            cnt++;
        }
    }
    printf("Case %d: average length between pages = %.3f clicks\n",++kase,1.0*sum/cnt);
}
int main()
{   kase=0;
    while(true){
        int x,y;
        scanf("%d%d",&x,&y);
        if(x==0&&y==0) break;
        Init();
        d[x][y]=1;
        while(true){
            int xx,yy;
              scanf("%d%d",&xx,&yy);
            if(xx==0&&yy==0) break;
            d[xx][yy]=1;
        }
        solve();
    }
    return 0;
}