Submission #1166183

#	Time	Username	Problem	Language	Result	Execution time	Memory
1166183		mannshah1211	Port Facility (JOI17_port_facility)	C++20	22 / 100	6094 ms	16968 KiB

port_facility

#include <bits/stdc++.h>

using namespace std;

#ifdef LOCAL
#include "deb.h"
#else
#define debug(...) 
#endif

const int M = 1e9 + 7;

void solve() {
  int n;
  cin >> n;
  vector<int> a(n), b(n), d(2 * n);
  for (int i = 0; i < n; i++) {
    cin >> a[i] >> b[i];
    --a[i]; --b[i];
    d[a[i]] = i + 1;
    d[b[i]] = -i - 1;
  }
  vector<vector<int>> g(n);
  auto Add = [&](int u, int v) -> void {
    --u; --v;
    g[u].push_back(v);
    g[v].push_back(u);
  };
  set<int> active;
  for (int i = 0; i < 2 * n; i++) {
    if (d[i] > 0) {
      active.insert(d[i]);
    } else {
      active.erase(-d[i]);
      for (int obstacle : active) {
        if (a[obstacle - 1] > a[-d[i] - 1]) {
          Add(obstacle, -d[i]);
        }
      }
    }
  }
  vector<int> c(n, -1);
  bool bipartite = true;
  int comps = 0;
  auto Dfs = [&](auto&& self, int v) -> void {
    for (int u : g[v]) {
      if (c[u] == c[v]) {
        bipartite = false;
        return;
      } else {
        if (c[u] == -1) {
          c[u] = c[v] ^ 1;
          self(self, u);
        }
      }
    }
  };
  for (int i = 0; i < n; i++) {
    if (c[i] == -1) {
      comps += 1;
      c[i] = 0;
      Dfs(Dfs, i);
    }
  }
  if (!bipartite) {
    cout << 0 << '\n';
    return;
  }
  int ans = 1;
  for (int i = 0; i < comps; i++) {
    ans *= 2;
    ans %= M;
  }
  cout << ans << '\n';
}

int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  int t = 1;
  // cin >> t;
  while (t--) {
    solve();
  }
  return 0;
}

• Subtask 1: 10 / 10
• Subtask 2: 12 / 12
• Subtask 3: 0 / 56
• Subtask 4: 0 / 22