20分求助

#include <bits/stdc++.h>
using namespace std;
unsigned long long sum=1,cnt=1;
int main(){
    unsigned long long n,m;
    cin>>n;
    for(int i=1;i<=n;i++){
    	unsigned long long m;  
        cin>>m;
		if(m==0)
		{
    	cout<<2<<endl;
    	continue;
		}
        for(int j=m-1;j>=1;j-=2)
		{
            sum*=j;
        }
        cout<<sum*2<<endl;
    }
    return 0;
}