Submission #537523

#	Time	Username	Problem	Language	Result	Execution time	Memory
537523		someone	Event Hopping 2 (JOI21_event2)	C++14	100 / 100	210 ms	27844 KiB

event2

#include <bits/stdc++.h>
#define int long long
using namespace std;

struct Inter {
    int deb, fin, id;
    
    bool operator <(const Inter& other) const {
        if(deb == other.deb)
            return fin < other.fin;
        return deb < other.deb;
    }
};

const int N = 1e5 + 42, T = 17, INF = 1e9 + 42;

set<Inter> ans;
vector<int> toPrint;
Inter inter[N], inter2[N];
int n, k, nb = 0, bl[T][N];

int getNb(int a, int b) {
    int ans = 0;
    for(int i = T-1; i > -1; i--)
        if(inter[bl[i][a]].fin <= inter[b].deb)
            a = bl[i][a], ans += (1 << i);
    return ans;
}

void tryInsert(int i) {
    if(((int)ans.size()) == k)
        return;
    auto it = ans.lower_bound(inter[i]);
    if(inter[i].fin > (*it).deb && (*it).fin > inter[i].deb)
        return;
    int aft = (*it).id;
    it--;
    if(inter[i].fin > (*it).deb && (*it).fin > inter[i].deb)
        return;
    int pre = (*it).id,
        ch = getNb(pre, i) + getNb(i, aft) + 1 - getNb(pre, aft);
    if(nb + ch >= k) {
        nb += ch;
        toPrint.push_back(i+1);
        ans.insert(inter[i]);
    }
}

signed main() {
    ios::sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);
    
    cin >> n >> k;
    for(int i = 0; i < n; i++)
        cin >> inter[i].deb >> inter[i].fin;
    inter[n].deb = (inter[n].fin = -INF) - 1;
    inter[n+1].deb = (inter[n+1].fin = INF) - 1;
    n += 2;
    for(int i = 0; i < n; i++)
        inter[i].id = i;
    
    for(int i = 0; i < n; i++)
        inter2[i].id = i,
        inter2[i].deb = inter[i].deb,
        inter2[i].fin = inter[i].fin;
    
    sort(inter, inter + n,
    [](Inter a, Inter b) {
        return a.deb > b.deb;
    });
    sort(inter2, inter2 + n,
    [](Inter a, Inter b) {
        return a.fin > b.fin;
    });
    
    int imin = -1;
    for(int i = 0, j = 0; i < n; i++) {
        while(j < n && inter[j].deb >= inter2[i].fin) {
            if(imin == -1 || inter[j].fin < inter[imin].fin)
                imin = j;
            j++;
        }
        bl[0][inter2[i].id] = inter[imin].id;
    }
    bl[0][n-1] = n-1;
    
    for(int i = 1; i < T; i++)
        for(int j = 0; j < n; j++)
            bl[i][j] = bl[i-1][bl[i-1][j]];
    
    sort(inter, inter + n,
    [](Inter a, Inter b) {
        return a.id < b.id;
    });
    n -= 2;
    k += 2;
    ans.insert(inter[n]);
    ans.insert(inter[n+1]);
    nb = 2 + getNb(n, n+1);
    for(int i = 0; i < n; i++)
        tryInsert(i);
    
    if(k-2 == (int)toPrint.size()) {
        for(int i : toPrint)
            cout << i << '\n';
    } else {
        cout << "-1";
    }
}

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