Submission #1231475

#	Time	Username	Problem	Language	Result	Execution time	Memory
1231475		omsincoconut	Event Hopping (BOI22_events)	C++17	0 / 100	34 ms	3396 KiB

events

#include <bits/stdc++.h>

using namespace std;
const int INF = 1e9;

int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);

    int N, Q;
    cin >> N >> Q;

    vector<int> S(N+1), E(N+1);
    for (int i = 1; i <= N; i++) cin >> S[i] >> E[i];

    int ord[N+1];
    iota(ord+1, ord+N+1, 1);
    sort(ord+1, ord+N+1, [&E, &S](int a, int b) {return (E[a] < E[b]) || (E[a] == E[b] && S[a] > S[b]);});

    int iord[N+1];
    for (int i = 1; i <= N; i++) iord[ord[i]] = i;

    int qc[N+1];
    qc[1] = 0;
    for (int i = 2; i <= N; i++) {
        qc[i] = qc[i-1] + (S[ord[i]] <= E[ord[i-1]] && E[ord[i-1]] <= E[ord[i]]);
    }

    while (Q--) {
        int s, e;
        cin >> s >> e;

        int is = iord[s], ie = iord[e];
        if (s == e) cout << 0 << "\n";
        else if (S[e] <= E[s] && E[s] <= E[e]) cout << 1 << "\n";
        else if (is > ie) cout << "impossible\n";
        else if (qc[ie] - qc[is] < ie-is) cout << "impossible\n";
        else cout << ie-is << "\n";
    }


    return 0;
}

/*
5 2
1 3
2 4
4 7
7 9
3 7
1 4
3 2
*/

/*
8 5
1 2
3 4
1 5
6 7
5 10
10 20
15 20
999999999 1000000000
1 6
1 7
2 4
3 3
5 8
*/

/*
3 9
1 2
2 3
3 4
1 1
1 2
1 3
2 1
2 2
2 3
3 1
3 2
3 3
*/

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