func_code_string: #include <bits/stdc++.h>   using namespace std;   const int maxn = 5e3 + 100;   int k;   long long a[20][maxn];   int nk[20];   map<long long, pair<int, int> > mp;   long long sum = 0;   bool _is[1 << 17];   long long tol[20];   bool _a[20][maxn];   vector<pair<int, int> > que;   vector<vector<pair<int, int> > > dp[1 << 17];   pair<int, int> ans[20];   void dfs(int fir, int i, int j, int sta, int &flag) {     if (a[i][j] == fir) {       if (_a[i][j] && !_is[sta]) {         _is[sta] = 1;         flag = 1;         dp[sta].push_back(que);         return;       }     }     if (_a[i][j]) return;     long long tmp = sum - (tol[i] - a[i][j]);     if (mp.find(tmp) == mp.end()) {       return;     }     int tfir = mp[tmp].first;     int tsec = mp[tmp].second;     if (sta >> tfir & 1) {       return;     }     _a[i][j] = 1;     que.push_back({tmp, i});     dfs(fir, tfir, tsec, sta | 1 << tfir, flag);     que.pop_back();     if (!flag) _a[i][j] = 0;   }   int main() {     ios::sync_with_stdio(false);     cin.tie(0);     cout.tie(0);     cin >> k;     for (int i = 0; i < k; ++i) {       cin >> nk[i];       for (int j = 0; j < nk[i]; ++j) {         cin >> a[i][j];         mp[a[i][j]] = {i, j};         sum += a[i][j];         tol[i] += a[i][j];       }     }     if (sum % k) {       cout <<  No  << endl;     } else {       sum /= k;       for (int i = 0; i < k; ++i) {         for (int j = 0; j < nk[i]; ++j) {           if (_a[i][j]) continue;           int tmp = 0;           dfs(a[i][j], i, j, 0, tmp);         }       }       for (int i = 1; i < 1 << k; ++i) {         if (!_is[i]) {           for (int j = i; j; j = j - 1 & i) {             if (_is[j] && _is[i ^ j]) {               for (auto l : dp[j]) {                 dp[i].push_back(l);               }               for (auto l : dp[i ^ j]) {                 dp[i].push_back(l);               }               _is[i] = 1;               break;             }           }         }       }       if (_is[(1 << k) - 1]) {         cout <<  Yes  << endl;         for (auto i : dp[(1 << k) - 1]) {           for (auto j : i) {             ans[mp[j.first].first] = j;           }         }         for (int i = 0; i < k; ++i) {           cout << ans[i].first <<     << ans[i].second + 1 << endl;         }       } else {         cout <<  No  << endl;       }     }     return 0;   }   