Submission #1217241

#	Time	Username	Problem	Language	Result	Execution time	Memory
1217241		woatjudge	Port Facility (JOI17_port_facility)	C++20	0 / 100	0 ms	320 KiB

port_facility

#include <bits/stdc++.h>

#define int long long
using namespace std;

#define L(i, j, k) for(int i = (j); i <= (k); ++i)
#define R(i, j, k) for(int i = (j); i >= (k); --i)

std::mt19937 rng(std::chrono::steady_clock::now().time_since_epoch().count());

const int MOD=1e9+7;
void solve() {
    int n;cin>>n;
    vector<pair<int,int>> vec(n);
    vector<bool> dead(n);
    vector<int> ev(2*n);
    L(i,0,n-1){
        cin>>vec[i].first>>vec[i].second;
        vec[i].first--;vec[i].second--;
        ev[vec[i].first]=i;
        ev[vec[i].second]=i;
    }


    set<pair<int,int>> ativo;
    vector<vector<int>> adj(n);
    L(i,0,2*n-1){
        if(!dead[ev[i]]){
            if(!ativo.empty()){
                auto pt=ativo.begin();
                auto [r,id]=*pt;

                if(r<vec[ev[i]].second){
                    adj[id].push_back(ev[i]);
                    adj[ev[i]].push_back(id);
                }
            }
            ativo.insert({vec[ev[i]].second,ev[i]});
            dead[ev[i]]=1;
        }
        else{
            ativo.erase({i,ev[i]});
        }
    }
    vector<int> cor(n,-1);
    auto dfscor=[&](auto&& self, int node, int pai)->void{
        cor[node]=cor[pai]^1;
        for(auto a:adj[node]){
            if(a==pai)continue;
            self(self,a,node);
        }
    };
    int cnt=0;
    L(i,0,n-1){
        if(cor[i]==-1){
            cor[i]=1;
            cnt++;
            dfscor(dfscor,i,i);
        }
    }


    {
        vector<vector<int>> st(2);
        L(i,0,n-1)dead[i]=0;
        L(i,0,2*n-1){
            int id=ev[i];
            if(dead[id]){
                if(st[cor[id]].empty() || st[cor[id]].back()!=id){
                    cout<<0;return;
                }
                st[cor[id]].pop_back();
            }
            else{
                dead[id]=1;
                st[cor[id]].push_back(id);
            }
        }
    }
    int potat=2;
    int resp=1;
    while(cnt>0){
        if(cnt%2)resp*=potat;
        cnt/=2;
        potat*=potat;
        resp%=MOD;
        potat%=MOD;
    }
    cout<<resp;
    return;





}
 
int32_t main() {
    std::cin.tie(0)->sync_with_stdio(0); 
    std::cin.exceptions(std::cin.failbit);

    int T = 1;
    while(T--) {
        solve();
    }

	return 0;
}

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