1146C - Tree Diameter - CodeForces Solution

#include<bits/stdc++.h>
// #define endl '\n'
#define x first
#define y second
#define pb push_back
#define lowbit(x) (x & (-x))
#define point(n) cout << fixed << setprecision(n)
#define YN(flag) cout << (flag ? "YES" : "NO") << endl
#define debug(x) cout << "debug " << x << endl
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
typedef pair<ll,ll> PLL;
typedef pair<ull,ull> UPLL;
typedef pair<int,int> PII;
typedef pair<double,double> PDD;
const int INF = 0x3f3f3f3f;
const ll mod = 1e9 + 7;
const double PI = acos(-1);
const double eps = 1e-7;
const int N = 1000010, M = 2 * N;


int n, m;

int ask(int x)
{
    vector<int> a, b;
    for(int i = 1; i <= n; i++)
    {
        if(i >> x & 1)
            a.push_back(i);
        else
            b.push_back(i);
    }
    // if(a.empty() || b.empty()) return 0;
    cout << a.size() << " " << b.size() << " ";
    for(auto e : a)
        cout << e << " ";
    for(auto e : b)
        cout << e << " ";
    cout << endl;
    int res;
    cin >> res;
    return res;
}

void solve()
{
    cin >> n;
    int ans = 0;
    for(int i = 0; i <= __lg(n); i++)
        ans = max(ans, ask(i));
    cout << "-1 " << ans << endl;
}

int main() 
{
    ios::sync_with_stdio(false), cin.tie(nullptr);
    int _ = 1;
    cin >> _;
    while(_--)
    {
        solve();
    }
}