Submission #999325

#	Time	Username	Problem	Language	Result	Execution time	Memory
999325		AdamGS	Port Facility (JOI17_port_facility)	C++17	0 / 100	1 ms	2396 KiB

port_facility

#include<bits/stdc++.h>
using namespace std;
typedef long double ld;
typedef long long ll;
#define rep(a, b) for(int a = 0; a < (b); ++a)
#define st first
#define nd second
#define pb push_back
#define all(a) a.begin(), a.end()
const ll MOD=1e9+7;
const int LIM=1e6+7;
pair<int,int>T[LIM];
int F[LIM], S[2*LIM], odw[LIM], sum[LIM];
int fnd(int x) {
  if(F[x]==x) return x;
  return F[x]=fnd(F[x]);
}
void uni(int a, int b) {
  if(fnd(a)==fnd(b)) return;
  F[fnd(b)]=fnd(a);
}
int main() {
  ios_base::sync_with_stdio(0); cin.tie(0);
  int n;
  cin >> n;
  rep(i, n) {
    cin >> T[i].st >> T[i].nd;
    --T[i].st; --T[i].nd;
  }
  sort(T, T+n);
  vector<int>A, B;
  A.pb(MOD);
  B.pb(MOD);
  rep(i, n) {
    while(A.back()<T[i].st) A.pop_back();
    while(B.back()<T[i].st) B.pop_back();
    if(T[i].nd>max(A.back(), B.back())) {
      cout << 0 << '\n';
      return 0;
    }
    if(A.back()<=B.back()) {
      if(T[i].nd<A.back()) A.pb(T[i].nd);
      else B.pb(T[i].nd);
    } else {
      if(T[i].nd<B.back()) B.pb(T[i].nd);
      else A.pb(T[i].nd);
    }
  }
  rep(i, n) F[i]=i;
  rep(i, n) {
    S[T[i].st]=i+1;
    S[T[i].nd]=-i-1;
  }
  vector<int>P;
  rep(i, 2*n) {
    int p=abs(S[i])-1;
    if(S[i]>0) {
      P.pb(p);
      continue;
    }
    odw[p]=1;
    ++sum[P.back()];
    --sum[p];
    while(P.size()>0 && odw[P.back()]) {
      int x=P.back(); P.pop_back();
      if(P.size()>0) {
        if(sum[x]) uni(x, P.back());
        sum[P.back()]+=sum[x];
      }
    }
  }
  ll ans=1;
  rep(i, n) if(fnd(i)==i) ans=(ans*2)%MOD;
  cout << ans << '\n';
}

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