Submission #590020

#	Time	Username	Problem	Language	Result	Execution time	Memory
590020		Morisz10	Event Hopping 2 (JOI21_event2)	C++14	100 / 100	214 ms	21996 KiB

event2

#include <bits/stdc++.h>
using namespace std;
using ll=long long;
const int maxn=100010;

struct event{
    ll l, r;
    int id;
    event(){}
    bool operator<(const event& e) const {
        if(l != e.l)return l < e.l;
        return r < e.r;
    }
};

event e[maxn];
int nxt[maxn][18];
bool was[maxn];

int cnt(int i, int j){
    int ans = 0;
//    int x=i;
    for(int k = 17; k >= 0; k--){
        if(e[nxt[i][k]].r <= e[j].l){
            i=nxt[i][k];
            ans+=(1<<k);
        }
    }
  //  cout<<'\n'<<x<<' '<<j<<' '<<ans<<'\n';
    return ans;
}

int main(){
    int n, k;
    cin >> n >> k;
    e[0].l=e[0].r=e[0].id=0;
    e[n + 1].l = 1e10;
    e[n + 1].r = 1e10 + 1;
    e[n + 1].id = n + 1;
    vector<pair<ll,int>> he{{0, 0}, {0, 0}};
    for(int i = 1; i <= n; i++){
        cin >> e[i].l >> e[i].r;
        e[i].id = i;
        he.push_back({e[i].l, i + n});
        he.push_back({e[i].r, i});
    }
    sort(he.begin(), he.end());
    for(int i=0;i<=n+1;i++){
        for(int j=0;j<18;j++)
            nxt[i][j] = n + 1;
    }
//    cout<<"a\n";
    int cur = -1;
    for(int i = he.size()-1; i >= 0; i--){
     //   cout<<i<<' '<<he[i].first<<' '<<he[i].second<<' '<<cur<<endl;
        if(he[i].second > n){
            if(cur < 0 || e[he[i].second - n].r< e[cur].r)
                cur = he[i].second - n;
        }
        else if(cur > 0){
            nxt[he[i].second][0]=cur;
            for(int j=1;j<18;j++){
                nxt[he[i].second][j] = nxt[nxt[he[i].second][j - 1]][j - 1];
            }
        }
    }
    vector<int> ans;
    set<event> s;
    int sum = cnt(0, n + 1);
    s.insert(e[0]);
    s.insert(e[n + 1]);
    for(int i = 1;i <= n && ans.size() < k; i++){
        auto R=s.upper_bound(e[i]), L=R;
        L--;
        if(R->l < e[i].r || L->r > e[i].l)continue;
        int x = cnt(L->id, R->id) - cnt(L->id, i) - cnt(i, R->id) - 1;
        if(sum - x < k)continue;
        sum -= x;
        ans.push_back(i);
        s.insert(e[i]);
    }
    if(ans.size() < k){
        cout<<-1;
        return 0;
    }
    for(int i:ans)cout<<i<<'\n';
    cout<<'\n';
}

Compilation message (stderr)

event2.cpp: In function 'int main()':
event2.cpp:72:40: warning: comparison of integer expressions of different signedness: 'std::vector<int>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
   72 |     for(int i = 1;i <= n && ans.size() < k; i++){
      |                             ~~~~~~~~~~~^~~
event2.cpp:82:19: warning: comparison of integer expressions of different signedness: 'std::vector<int>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
   82 |     if(ans.size() < k){
      |        ~~~~~~~~~~~^~~

• Subtask 1: 7 / 7
• Subtask 2: 1 / 1
• Subtask 3: 31 / 31
• Subtask 4: 61 / 61