Submission #583653

#	Time	Username	Problem	Language	Result	Execution time	Memory
583653		tutis	Event Hopping (BOI22_events)	C++17	25 / 100	245 ms	524288 KiB

events

/*input
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
*/
#include <bits/stdc++.h>
using namespace std;
int main()
{
	ios_base::sync_with_stdio(false);
	cin.tie(0);
	cout.tie(0);
	int N, Q;
	cin >> N >> Q;
	pair<pair<int, int>, int>A[N];
	for (int i = 0; i < N; i++)
	{
		cin >> A[i].first.second >> A[i].first.first;
		A[i].second = i;
	}
	sort(A, A + N);
	int p[N];
	for (int i = 0; i < N; i++)
		p[A[i].second] = i;
	int S[N], E[N];
	for (int i = 0; i < N; i++)
	{
		S[i] = A[i].first.second;
		E[i] = A[i].first.first;
	}
	for (int i = 0; i < N; i++)
	{
		S[i] = (lower_bound(E, E + N, S[i]) - E);
	}
	int D[N][N];
	for (int i = 0; i < N; i++)
		for (int j = 0; j < N; j++)
			D[i][j] = N + 10;
	for (int j = 0; j < N; j++)
	{
		if (S[j] >= j)
			continue;
		pair<int, int>mn = { N + 1, N + 1};
		for (int i = S[j]; i < j; i++)
		{
			D[j][i] = 1;
			mn = min(mn, {S[i], i});
		}
		for (int i = 0; i < S[j]; i++)
			D[j][i] = D[mn.second][i] + 1;
	}
	while (Q--)
	{
		int s, t;
		cin >> s >> t;
		s = p[s - 1];
		t = p[t - 1];
		if (s == t)
		{
			cout << "0\n";
		}
		else {
			if (A[t].first.second <= A[s].first.first && A[s].first.first <= A[t].first.first)
				cout << "1\n";
			else {
				int k = D[t][s];
				if (k > N)
					cout << "impossible\n";
				else
					cout << k << "\n";
			}
		}
	}
}

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