#include<iostream>
#include<cmath>
#include<iomanip>
#include<algorithm>
#include<cstdlib>
#include<cstring>
#include<vector>
#include<utility>

#define ll long long
#define sz(x) int(x.size())
#define all(x) x.begin(),x.end()
using namespace std;

void Fast_IO(){
    ios_base::sync_with_stdio(false), cin.tie(nullptr), cout.tie(nullptr);
    #ifndef ONLINE_JUDGE
        freopen("input.txt", "r", stdin), freopen("output.txt", "w", stdout);
    #endif
}





void solve(){
  ll n; cin>>n;
  ll arr[n];
for(ll i=0; i<n; i++){
    cin>>arr[i];
}
sort(arr,arr+n);
if(arr[0]<0 && arr[1]<0){
    if(arr[0]*arr[1]+arr[1]-arr[0]>= arr[n-1]*arr[n-2]+arr[n-1]-arr[n-2]) cout<<arr[1]*arr[0]+arr[1]-arr[0];
    else cout<<arr[n-1]*arr[n-2]+arr[n-1]-arr[n-2];
}else cout<<arr[n-1]*arr[n-2]+arr[n-1]-arr[n-2];

cout<<'\n';

}

int main(){
    Fast_IO();
int t =1;
cin>>t;
while(t--){
solve();
}
return 0;
}