Submission #404776

#	Time	Username	Problem	Language	Result	Execution time	Memory
404776		rama_pang	Political Development (BOI17_politicaldevelopment)	C++17	100 / 100	271 ms	10604 KiB

politicaldevelopment

#include <bits/stdc++.h>
using namespace std;

int main() {
  ios::sync_with_stdio(0);
  cin.tie(0);

  int N, K;
  cin >> N >> K;

  vector<int> deg(N);
  vector<vector<int>> adj(N);
  for (int u = 0; u < N; u++) {
    int sz;
    cin >> sz;
    while (sz--) {
      int v;
      cin >> v;
      deg[u]++;
      adj[u].emplace_back(v);
    }
  }

  vector<int> done(N);
  priority_queue<pair<int, int>> pq;
  for (int u = 0; u < N; u++) {
    sort(begin(adj[u]), end(adj[u]));
    pq.emplace(-deg[u], u);
  }

  int ans = 0;
  while (!pq.empty()) {
    int mn = pq.top().second;
    pq.pop();
    if (done[mn]) {
      continue;
    }

    done[mn] = 1;
    static vector<int> ls; ls = {mn};
    for (auto v : adj[mn]) if (!done[v]) {
      ls.emplace_back(v);
      deg[v]--;
      pq.emplace(-deg[v], v);
    }

    int n = ls.size();
    assert(n <= K);
    static array<int, 10> arr;
    for (int i = 0; i < n; i++) {
      arr[i] = 1 << i;
    }
    for (int i = 0; i < n; i++) {
      for (int j = i + 1; j < n; j++) {
        int u = ls[i], v = ls[j];
        if (binary_search(begin(adj[u]), end(adj[u]), v)) {
          arr[i] |= 1 << j;
          arr[j] |= 1 << i;
        }
      }
    }
    for (int mask = 1; mask < (1 << n); mask++) {
      int valid = mask;
      for (int i = 0; i < n; i++) if ((mask >> i) & 1) {
        valid &= arr[i];
      }
      if (valid == mask) {
        ans = max(ans, __builtin_popcount(mask));
      }
    }
  }

  cout << ans << '\n';
  return 0;
}

• Subtask 1: 4 / 4
• Subtask 2: 12 / 12
• Subtask 3: 23 / 23
• Subtask 4: 38 / 38
• Subtask 5: 23 / 23