func_code_string: #include <bits/stdc++.h>   using namespace std;   const int inf = 0x3f3f3f3f, mod = 1000000007;   const long long INF = 0x3f3f3f3f3f3f3f3fLL;   const double pi = acosl(-1.), eps = 1e-9;   inline int power(int a, int b, int m = mod, int ans = 1) {     for (; b; b >>= 1, a = 1LL * a * a % m)       if (b & 1) ans = 1LL * ans * a % m;     return ans;   }   int que(vector<int> a, vector<int> b) {     printf( %d %d  , a.size(), b.size());     for (auto r : a) cout << r <<    ;     for (auto r : b) cout << r <<    ;     fflush(stdout);     int ans;     cin >> ans;     return ans;   }   int main() {     int T;     cin >> T;     while (T--) {       int n;       scanf( %d , &n);       vector<int> a, b;       a.push_back(1);       for (int i = 2; i <= n; i++) b.push_back(i);       int t = que(a, b);       int st = 1, ed = n;       while (st + 1 < ed) {         int md = st + ed >> 1;         b.clear();         for (int i = 2; i <= md; i++) b.push_back(i);         if (que(a, b) == t)           ed = md;         else           st = md;       }       a.clear();       b.clear();       a.push_back(ed);       for (int i = 1; i <= n; i++)         if (ed != i) b.push_back(i);       t = que(a, b);       printf( -1 %d n , t);       fflush(stdout);     }     return 0;   }   