Submission #961176

#	Time	Username	Problem	Language	Result	Execution time	Memory
961176		abczz	Port Facility (JOI17_port_facility)	C++14	10 / 100	9 ms	6748 KiB

port_facility

#include <iostream>
#include <vector>
#include <array>
#include <map>
#define ll long long

using namespace std;

ll n, s, f = 1, X[1000000], P[1000000], M = 1e9 + 7;
vector <ll> V, U;
map <ll, ll> mp;
bool B[1000000];
array <ll, 2> A[1000000], R[1000000];
ll dsu(ll u) {
  if (u == P[u]) return u;
  else return P[u] = dsu(P[u]);
}
int main() {
  cin.tie(0);
  ios::sync_with_stdio(0);
  cin >> n;
  for (int i=0; i<n; ++i) {
    P[i] = i;
    cin >> R[i][0] >> R[i][1];
    --R[i][0], --R[i][1];
    A[R[i][0]] = {i, 0}, A[R[i][1]] = {i, 1};
  }
  for (int i=0; i<2*n; ++i) {
    if (!A[i][1]) {
      auto it = mp.lower_bound(R[A[i][0]][1]);
      if (it != mp.begin()) {
        it = prev(it);
        X[A[i][0]] = it->first;
      }
      else X[A[i][0]] = -1e18;
      ++mp[R[A[i][0]][1]];
    }
  }
  mp.clear();
  for (int i=2*n-1; i>=0; --i) {
    if (A[i][1]) {
      auto it = mp.lower_bound(R[A[i][0]][0]);
      if (it != mp.end() && X[A[i][0]] != -1e18 && it->first < X[A[i][0]]) {
        cout << "0\n";
        return 0;
      }
      ++mp[R[A[i][0]][0]];
    }
  }
  for (int i=0; i<2*n; ++i) {
    if (A[i][1]) {
      while (!V.empty()) {
        auto u = V.back();
        if (R[u][0] < R[A[i][0]][0]) break;
        V.pop_back();
        if (!B[u]) {
          //cout << R[u][0]+1 << " " << R[u][1]+1 << " " << R[A[i][0]][0]+1 << " " << R[A[i][0]][1]+1 << endl;
          U.push_back(u);
          P[dsu(u)] = dsu(A[i][0]);
        }
      }
      while (!U.empty()) {
        auto u = U.back();
        U.pop_back();
        V.push_back(u);
      }
      B[A[i][0]] = 1;
    }
    else V.push_back(A[i][0]);
  }
  mp.clear();
  for (int i=0; i<n; ++i) {
    ++mp[dsu(i)];
  }
  for (int i=0; i<mp.size(); ++i) {
    f *= 2;
    f %= M;
  }
  cout << f << '\n';
}

Compilation message (stderr)

port_facility.cpp: In function 'int main()':
port_facility.cpp:75:18: warning: comparison of integer expressions of different signedness: 'int' and 'std::map<long long int, long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   75 |   for (int i=0; i<mp.size(); ++i) {
      |                 ~^~~~~~~~~~

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