POJ 1862 Stripies

#include<iostream>
#include<queue>
#include<cmath>
#include<cstdio>
using namespace std;
priority_queue<double>que;
int main()
{
int N;
cin>>N;
int i=0;
for(;i<N;i++)
{
double c;
cin>>c;
que.push(c);
}
while(que.size()>1)
{
double a=que.top();
que.pop();
double b=que.top();
que.pop();
double c=2*sqrt(a*b);
que.push(c);
}
printf("%.3f\n",que.top());
return 0;
}