Submission #569967

#	Time	Username	Problem	Language	Result	Execution time	Memory
569967		600Mihnea	Potemkin cycle (CEOI15_indcyc)	C++17	0 / 100	3 ms	340 KiB

indcyc

#include <bits/stdc++.h>

using namespace std;

const int N = 1000 + 7;
const int INF = (int) 1e9 + 7;
int n, m, dist[N], par[N];
vector<int> g[N];


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

  freopen ("input.txt", "r", stdin);

  cin >> n >> m;
  for (int i = 1; i <= m; i++) {
    int a, b;
    cin >> a >> b;
    g[a].push_back(b);
    g[b].push_back(a);
  }
  for (int i = 1; i <= n; i++) {
    sort(g[i].begin(), g[i].end());
  }
  for (int root = 1; root <= n; root++) {
    for (auto &v1 : g[root]) {
      for (auto &v2 : g[root]) {
        if (v1 == v2) continue;
        for (int i = 1; i <= n; i++) {
          dist[i] = INF;
          par[i] = 0;
        }
        dist[root] = -1;
        for (auto &v : g[root]) {
          if (v != v1 && v != v2) {
            dist[v] = -1;
          }
        }
        queue<int> q;
        dist[v1] = 0;
        q.push(v1);
        while (!q.empty()) {
          int a = q.front();
          q.pop();
          for (auto &b : g[a]) {
            if (dist[b] == INF) {
              dist[b] = 1 + dist[a];
              par[b] = a;
              q.push(b);
            }
          }
        }
        if (dist[v2] == 1) continue;
        if (dist[v2] != -1 && dist[v2] != INF) {
          while (v2 != v1) {
            cout << v2 << " ";
            v2 = par[v2];
          }
          cout << v1 << " " << root << "\n";
          return 0;
        }
      }
    }
  }
  cout << "no\n";
  exit(0);
}

Compilation message (stderr)

indcyc.cpp: In function 'int main()':
indcyc.cpp:14:11: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   14 |   freopen ("input.txt", "r", stdin);
      |   ~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 0 / 10
• Subtask 2: 0 / 10
• Subtask 3: 0 / 10
• Subtask 4: 0 / 10
• Subtask 5: 0 / 10
• Subtask 6: 0 / 10
• Subtask 7: 0 / 10
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• Subtask 9: 0 / 10
• Subtask 10: 0 / 10