제출 #850060

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
850060		MinaRagy06	Event Hopping (BOI22_events)	C++17	30 / 100	180 ms	55004 KiB

events

#include <bits/stdc++.h>
using namespace std;
typedef int64_t ll;
 
const int N = 200'005;
array<int, 2> a[N];
int bl[18][N];
vector<array<int, 2>> st[2 * N], en[2 * N];
int main() {
    ios_base::sync_with_stdio(0), cin.tie(0);
    int n, q;
    cin >> n >> q;
    set<int> times;
    for (int i = 0; i < n; i++) {
        cin >> a[i][0] >> a[i][1];
        times.insert(a[i][0]), times.insert(a[i][1]);
    }
    vector<int> v;
    for (auto i : times) {
        v.push_back(i);
    }
    for (int i = 0; i < n; i++) {
        st[lower_bound(v.begin(), v.end(), a[i][0]) - v.begin()].push_back({i, a[i][1]});
        en[lower_bound(v.begin(), v.end(), a[i][1]) - v.begin()].push_back({i, a[i][1]});
    }
    multiset<array<int, 2>> s;
    for (int i = v.size() - 1; i >= 0; i--) {
        for (auto [idx, t] : en[i]) {
            s.insert({-t, idx});
        }
        for (auto [idx, t] : en[i]) {
            bl[0][idx] = (*s.begin())[1];
        }
        for (auto [idx, t] : st[i]) {
            s.erase(s.find({-t, idx}));
        }
    }
    for (int j = 1; j < 18; j++) {
        for (int i = 0; i < n; i++) {
            bl[j][i] = bl[j - 1][bl[j - 1][i]];
        }
    }
    while (q--) {
        int s, e;
        cin >> s >> e;
        s--, e--;
        if (s == e) {
            cout << "0\n";
            continue;
        }
        if (a[e][0] <= a[s][1] && a[s][1] <= a[e][1]) {
            cout << "1\n";
            continue;
        }
        int ans = 0;
        for (int j = 17; j >= 0; j--) {
            int New = bl[j][s];
            if (!(a[e][0] <= a[New][1] && a[New][1] <= a[e][1]) && a[New][1] <= a[e][1]) {
                s = New;
                ans += (1 << j);
            }
        }
        ans++;
        s = bl[0][s]; 
        if (!(a[e][0] <= a[s][1] && a[s][1] <= a[e][1])) {
            cout << "impossible\n";
            continue;
        }
        cout << ans + 1 << '\n';
    }
    return 0;
}

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