POJ 1862 Stripies

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

int n,s;
priority_queue<double>Q;

int main()
{
while(~scanf("%d",&n))
{
while(!Q.empty())Q.pop();
for(int i=1; i<=n; i++)
{
double x;
scanf("%lf",&x);
Q.push(x);
}

s=n;
if(s==1)printf("%.3f\n",Q.top());
else
{
while(1)
{
double num1=Q.top();
Q.pop();
s--;
double num2=Q.top();
Q.pop();
s--;
Q.push(2*sqrt(num1*num2));
s++;
if(s==1)
{
printf("%.3f\n",Q.top());
break;
}
}
}
}
return 0;
}