Submission #1094701

#	Time	Username	Problem	Language	Result	Execution time	Memory
1094701		razivo	Event Hopping (BOI22_events)	C++14	0 / 100	1554 ms	12864 KiB

events

#include <iostream>
#include <climits>
#include <algorithm>
#include <set>
#include <vector>
using namespace std;
int main()
{
    int N,Q;
    cin>>N>>Q;
    vector<pair<pair<int,int>,int>> ev;
    vector<pair<pair<int,int>,int>> u;
    for (int i = 0; i < N; ++i) {
        int x,y;
        cin>>x>>y;
        ev.emplace_back(make_pair(x,y),i);
    }
    sort(ev.begin(),ev.end(),[](pair<pair<int,int>,int> a, pair<pair<int,int>,int> b){return b.first.second>a.first.second;});
    vector<int> intoev(N);
    for (int i = 0; i < N; ++i) {
        intoev[ev[i].second]=i;
        u.emplace_back(make_pair(ev[i].first.first,0),i);
        u.emplace_back(make_pair(ev[i].first.second,1),i);
    }
    sort(u.begin(),u.end());
    vector<int> f(N);
    set<pair<int,int>> s;
    for (int i = 0; i < 2*N; ++i) {
        auto [a,j] = u[i];
        if(ev[j].first.first==a.first) {
            s.insert({ev[j].first.second,j});
            auto t = s.lower_bound({0,0});
            if(t!=s.end()) {
                f[j]=t->second;
            }else f[j]=j;
        }else {
            s.erase({ev[j].first.second,j});
        }
    }
    vector<pair<pair<int,int>,int>> req;
    for (int i = 0; i < Q; ++i) {
        int s,e;
        cin>>s>>e; s--; e--;
        req.emplace_back(make_pair(intoev[s],intoev[e]),i);
    }
    vector<int> ans(Q);
    sort(req.begin(),req.end(),[](pair<pair<int,int>,int> a, pair<pair<int,int>,int> b){return b.first.second>a.first.second;});
    int cureq = 0;
    vector<pair<int,int>> intervals;
    vector<int> achiv(N);
    for (int i = 0; i < N; ++i) {
        if(f[i]==i) {
            intervals.emplace_back(i,i);
            achiv[i]=i;
        }else {
            achiv[i]=achiv[f[i]];
            while(intervals.back().first>f[i]) intervals.pop_back();
            if(intervals.back().first==f[i]) {
                intervals.back().second = i;
            }else {
                intervals.back().second = f[i]-1;
                intervals.emplace_back(f[i],i);
            }
        }
        while(req[cureq].first.second==i) {
            if(req[cureq].first.first==req[cureq].first.second) {
                ans[req[cureq].second] = 0;
                cureq++;
                continue;
            }
            if(req[cureq].first.first<achiv[i]) {
                ans[req[cureq].second] = -1;
                cureq++;
                continue;
            }else{
                int min = 0;
                int max = intervals.size();
                while(true) {
                    int mid = (max+min)/2;
                    if(req[cureq].first.first<intervals[mid].first) {
                        max = mid;
                    }else if(req[cureq].first.first>intervals[mid].second) {
                        min = mid;
                    }else {
                        ans[req[cureq].second] = intervals.size()-mid;
                        cureq++;
                        break;
                    }
                }
            }
        }
    }
    for (int i = 0; i < Q; ++i) {
        if(ans[i]==-1) {
            cout<<"impossible"<<endl;
        }else {
            cout<<ans[i]<<endl;
        }
    }
}

Compilation message (stderr)

events.cpp: In function 'int main()':
events.cpp:29:14: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
   29 |         auto [a,j] = u[i];
      |              ^

• Subtask 1: 0 / 10
• Subtask 2: 0 / 10
• Subtask 3: 0 / 15
• Subtask 4: 0 / 15
• Subtask 5: 0 / 20
• Subtask 6: 0 / 30