Submission #569986

#	Time	Username	Problem	Language	Result	Execution time	Memory
569986		600Mihnea	Potemkin cycle (CEOI15_indcyc)	C++17	70 / 100	1088 ms	2056 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];


bool is_edge(int a, int b) {
  int low = 0, high = (int) g[a].size() - 1;
  while (low <= high) {
    int mid = (low + high) / 2;
    if (g[a][mid] == b) {
      return 1;
    }
    if (g[a][mid] < b) {
      low = mid + 1;
    } else {
      high = mid - 1;
    }
  }
  return 0;
}

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) break;
        if (is_edge(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";
          exit(0);
        }
      }
    }
  }
  cout << "no\n";
  exit(0);
}

• Subtask 1: 10 / 10
• Subtask 2: 10 / 10
• Subtask 3: 10 / 10
• Subtask 4: 10 / 10
• Subtask 5: 10 / 10
• Subtask 6: 10 / 10
• Subtask 7: 10 / 10
• Subtask 8: 0 / 10
• Subtask 9: 0 / 10
• Subtask 10: 0 / 10