Submission #1001651

#	Time	Username	Problem	Language	Result	Execution time	Memory
1001651		MilosMilutinovic	Amusement Park (CEOI19_amusementpark)	C++14	19 / 100	3052 ms	460 KiB

amusementpark

#include <bits/stdc++.h>

using namespace std;

int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  int n, m;
  cin >> n >> m;
  vector<int> a(m), b(m);
  for (int i = 0; i < m; i++) {
    cin >> a[i] >> b[i];
    --a[i]; --b[i];
  }
  vector<vector<int>> g(n);
  auto Check = [&]() {
    vector<int> deg(n);
    for (int i = 0; i < n; i++) {
      for (int j : g[i]) {
        deg[j] += 1;
      }
    }
    vector<int> que;
    for (int i = 0; i < n; i++) {
      if (deg[i] == 0) {
        que.push_back(i);
      }
    }
    for (int b = 0; b < (int) que.size(); b++) {
      int i = que[b];
      for (int j : g[i]) {
        deg[j] -= 1;
        if (deg[j] == 0) {
          que.push_back(j);
        }
      }
    }
    return (int) que.size() == n;
  };
  int res = 0;
  for (int mask = 0; mask < (1 << m); mask++) {
    for (int i = 0; i < n; i++) {
      g[i].clear();
    }
    for (int i = 0; i < m; i++) {
      if (mask >> i & 1) {
        g[b[i]].push_back(a[i]);
      } else {
        g[a[i]].push_back(b[i]);
      }
    }
    if (Check()) {
      res += __builtin_popcount(mask);
    }
  }
  cout << res << '\n';
  return 0;
}

• Subtask 1: 7 / 7
• Subtask 2: 12 / 12
• Subtask 3: 0 / 23
• Subtask 4: 0 / 21
• Subtask 5: 0 / 37