Submission #1059319

#	Time	Username	Problem	Language	Result	Execution time	Memory
1059319		MilosMilutinovic	Potemkin cycle (CEOI15_indcyc)	C++14	80 / 100	1029 ms	126800 KiB

indcyc

#include <bits/stdc++.h>
 
using namespace std;
 
int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  int n, m;
  cin >> n >> m; 
  vector<vector<bool>> c(n, vector<bool>(n));
  vector<vector<int>> g(n);
  for (int i = 0; i < m; i++) {
    int x, y;
    cin >> x >> y;
    --x; --y;
    c[x][y] = true;
    c[y][x] = true;
    g[x].push_back(y);
    g[y].push_back(x);
  }
  const int N = 1005;
  vector<vector<bitset<N>>> bs(n, vector<bitset<N>>(n));
  for (int k = 0; k < n; k++) {
    vector<bool> del(n);
    del[k] = true;
    for (int i : g[k]) {
      del[i] = true;
    }
    vector<int> p(n);
    iota(p.begin(), p.end(), 0);
    vector<int> sz(n, 1);
    function<int(int)> Root = [&](int x) {
      return p[x] == x ? x : p[x] = Root(p[x]);
    };
    auto Merge = [&](int x, int y) {
      x = Root(x);
      y = Root(y);
      if (x == y) {
        return;
      }
      if (sz[x] < sz[y]) {
        swap(x, y);
      }
      sz[x] += sz[y];
      p[y] = x;
    };
    for (int i = 0; i < n; i++) {
      if (del[i]) {
        continue;
      }
      for (int j : g[i]) {
        if (del[j]) {
          continue;
        }
        Merge(i, j);
      }
    }
    vector<bool> was(n);
    for (int i = 0; i < n; i++) {
      if (!del[i]) {
        continue;
      }
      vector<int> xs;
      for (int j : g[i]) {
        if (del[j]) {
          continue;
        }
        xs.push_back(Root(j));
        if (!was[xs.back()]) {
          was[xs.back()] = true;
          bs[k][i][xs.back()] = 1;
        }
      }
      for (int x : xs) {
        was[x] = false;
      }
    }
  }
  for (int i = 0; i < n; i++) {
    for (int j = i + 1; j < n; j++) {
      if (c[i][j]) {
        continue;
      }
      for (int k : g[g[i].size() < g[j].size() ? i : j]) {
        if (i == k || j == k || !c[i][k] || !c[j][k]) {
          continue;
        }
        if ((bs[k][i] & bs[k][j]).count() == 0) {
          continue;
        }
        vector<bool> del(n);
        del[k] = true;
        for (int p : g[k]) {
          if (p != i && p != j) {
            del[p] = true;
          }
        }
        vector<int> p(n, -1);
        vector<int> que(1, i);
        vector<int> d(n, -1);
        d[i] = 0;
        for (int b = 0; b < (int) que.size(); b++) {
          int i = que[b];
          for (int j : g[i]) {
            if (del[j]) {
              continue;
            }
            if (d[j] == -1) {
              p[j] = i;
              d[j] = d[i] + 1;
              que.push_back(j);
            }
          }
        }
        if (p[j] == -1) {
          assert(false);
          continue;
        }
        vector<int> seq;
        for (int v = j; v != -1; v = p[v]) {
          seq.push_back(v);
        }
        seq.push_back(k);
        for (int i = 0; i < (int) seq.size(); i++) {
          cout << seq[i] + 1 << " ";
        }
        cout << '\n';
        return 0;
      }
    }
  }
  cout << "no" << '\n';
  return 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: 10 / 10
• Subtask 10: 0 / 10