poj1862

简单题

#include <iostream>
#include <cstdlib>
#include <cstdio>
#include <cstring>
#include <algorithm>
#include <cmath>
using namespace std;

#define maxn 105

int n;
int f[maxn];

int main()
{
    //freopen("t.txt", "r", stdin);
    scanf("%d", &n);
    for (int i = 0; i < n; i++)
        scanf("%d", &f[i]);
    sort(f, f + n);
    double ans = f[n - 1];
    for (int i = n - 2; i >= 0; i--)
        ans = 2 * sqrt(ans * f[i]);
    printf("%.3f\n", ans);
}