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#include <bits/stdc++.h> #define int long long using namespace std; int32_t main() { ios_base::sync_with_stdio(false); cin.tie(NULL); int t; cin >> t; while (t--) { int m; cin >> m; vector<vector<int>> v(m); for (int i = 0; i < m; ++i) { int n; cin >> n; v[i].resize(n); for (int j = 0; j < n; ++j) { cin >> v[i][j]; } } vector<int> result(m); set<int> used; bool f = true; for (int i = m - 1; i >= 0; --i) { bool found = false; for (int it : v[i]) { if (used.count(it) == 0) { result[i] = it; used.insert(it); found = true; }used.insert(it); } if (!found) { f = false; break; } } if (f) { for (int i = 0; i < result.size(); ++i) { if (i != 0) cout << " "; cout << result[i]; } cout << endl; } else { cout << -1 << endl; } } return 0; }
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