Submission #967140

#	Time	Username	Problem	Language	Result	Execution time	Memory
967140		ttamx	Port Facility (JOI17_port_facility)	C++17	0 / 100	0 ms	344 KiB

port_facility

#include<bits/stdc++.h>

using namespace std;

const int N=2e6+5;
const int MOD=1e9+7;

int n;
int p[N];
int ans=1;
stack<pair<int,int>> s;

int main(){
    cin.tie(nullptr)->sync_with_stdio(false);
    cin >> n;
    for(int i=0;i<n;i++){
        int x;
        cin >> x >> p[x];
    }
    s.emplace(2*n+1,0);
    for(int i=1;i<=2*n;i++)if(p[i]){
        while(i>s.top().first)s.pop();
        auto &[mx,mx2]=s.top();
        if(p[i]>mx){
            if(i<mx2)cout << 0,exit(0);
            else mx2=mx,mx=p[i];
        }else{
            if(i<mx2&&mx2<p[i])mx2=p[i];
            else{
                s.emplace(p[i],i);
                ans*=2;
                if(ans>=MOD)ans-=MOD;
            } 
        }
    }
    cout << ans;
}

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