OJ-Problems-Source/HDOJ/4586_autoAC.cpp

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#include <stdio.h>
#include <iostream>
#include <map>
#include <stack>
#include <vector>
#include <math.h>
#include <string.h>
#include <queue>
#include <string>
#include <stdlib.h>
#include <algorithm>
#define LL long long
#define _LL __int64
#define eps 1e-8
#define PI acos(-1.0)
using namespace std;
int n,m;
int vis[210];
int a[210];
int sum,cnt;
double p,q;
int main()
{
while(~scanf("%d",&n))
{
sum = 0;
cnt = 0;
memset(vis,0,sizeof(vis));
for(int i = 1; i <= n; i++)
{
cin >> a[i];
sum += a[i];
}
p = (sum*1.0)/n;
scanf("%d",&m);
int x;
for(int i = 1; i <= m; i++)
{
cin >> x;
if(vis[x]) continue;
cnt++;
vis[x] = 1;
}
q = (cnt*1.0)/n;
if(fabs(p) < eps)
cout << "0.00" << endl;
else if(fabs(q-1) < eps)
cout << "inf" << endl;
else
printf("%.2lf\n",p/(1-q));
}
return 0;
}