http://lx.lanqiao.cn/problem.page?gpid=T136
#include <bits/stdc++.h>
using namespace std;
const int maxn=20;
const int INF=0x3f3f3f3f;
int a[maxn];
int n,m;
int main(){
int T;
cin >> T;
while (T--){
cin >> n >> m;
for (int i=0;i<n;i++){
cin >> a[i];
}
sort(a,a+n);
int l=0,r=n-1;
int ans=1;
while (l<=n-1&&r>=0&&m>0){
if (a[l]*a[l+1]>a[r]*a[r-1]&&m>=2){
ans*=(a[l]*a[l+1]);
l+=2;
m-=2;
}
else{
ans*=a[r];
r-=1;
m-=1;
}
}
cout << ans << endl;
}
}