Submission #259990

#	Time	Username	Problem	Language	Result	Execution time	Memory
259990		Haunted_Cpp	Potemkin cycle (CEOI15_indcyc)	C++17	30 / 100	1096 ms	2148 KiB

indcyc

/**
 *  author: Haunted_Cpp
**/
 
#include <bits/stdc++.h>
using namespace std;
 
#pragma GCC optimize("Ofast")
#pragma GCC target("fma,sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,avx2,tune=native")
#pragma GCC optimize("unroll-loops")
 
template<typename T> ostream &operator << (ostream &os, const vector<T> &v) { os << '{'; string sep; for (const auto &x : v) os << sep << x, sep = ", "; return os << '}'; }
template<typename T, size_t size> ostream &operator << (ostream &os, const array<T, size> &arr) { os << '{'; string sep; for (const auto &x : arr) os << sep << x, sep = ", "; return os << '}'; }
template<typename A, typename B> ostream &operator << (ostream &os, const pair<A, B> &p) { return os << '(' << p.first << ", " << p.second << ')'; }
 
void debug_out() { cerr << endl; }
template<typename Head, typename... Tail> void debug_out(Head H, Tail... T) { cerr << ' ' << H; debug_out(T...); }
 
#ifdef LOCAL
#define debug(...) cerr << "(" << #__VA_ARGS__ << "):", debug_out(__VA_ARGS__)
#else
#define debug(...) 47
#endif

const int MAX_N = 1e3 + 5;

vector<vector<int>> g(MAX_N);

bool vis[MAX_N];
deque<int> stk;

int source;

bool solve(int node) {
  //~ debug(node);
  vis[node] = true;
  stk.push_back(node);
  bool res = false;
  for (auto to : g[node]) {
    if (to == source) {
      // CHECK
      vector<int> cycle;
      for (auto cur : stk) {
        cycle.emplace_back(cur);
      }
      //~ cout << "YES" << '\n';
      //~ debug(cycle);
      if ((int)cycle.size() < 4) {
        continue;
      }
      bool work = true;
      for (auto current : cycle) {
        int cnt = 0;
        //~ debug(current);
        for (auto nxt : cycle) {
          //~ debug(nxt);
          //~ debug(find(g[current].begin(), g[current].end(), nxt) != g[current].end());
          cnt += (find(g[current].begin(), g[current].end(), nxt) != g[current].end());
        }
        work &= (cnt == 2);
        //~ debug(cnt);
      }
      res |= work;
      if (work) {
        for(auto ans : cycle) {
          cout << ans + 1 << ' ';
        }
        cout << '\n';
        return true;
      }
      continue;
    }
    if (!vis[to]) {
      vis[to] = true;
      res |= solve(to);
    }
  }
  stk.pop_back();
  vis[node] = false;
  return res;
}

int main () {
  ios::sync_with_stdio(0);
  cin.tie(0);
  int n, m;
  cin >> n >> m;
  for (int i = 0; i < m; i++) {
    int st, et;
    cin >> st >> et;
    --st; --et;
    g[st].emplace_back(et);
    g[et].emplace_back(st);
  }
  //~ source = 1;
  //~ solve(1);
  for (int i = 0; i < n; i++) {
    source = i;
    if(solve(i)) {
      memset(vis, false, sizeof(vis));
      return 0;
    }
  }
  cout << "no" << '\n';
  return 0;
}

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