jREneO - Online C++0x Compiler & Debugging Tool

#include <iostream>
using namespace std;
int main() {
	int t;
	cin>>t;
	while(t--){
		int n;
		cin>>n;
		int a[n+1], pr[n+1]={0,};
		for(int i=1; i<=n; i++){
			cin>>a[i];
			pr[i]=pr[i-1]+a[i];
		}
	int l=1, r=n;
	while(l<r){
		int m=(l+r)/2;
		cout<<"? "<<m-l+1<<" ";
		for(int i=l; i<=m; i++)
		cout<<i<<" ";
		cout<<endl;
	 int x;
	 cin>>x;
	 if(x==pr[m]-pr[l-1])
	 	l=m+1;
	 else
		r=m;
	}
	cout<<"! "<<l<<endl;
		}
	}