Submission #528861

#	Time	Username	Problem	Language	Result	Execution time	Memory
528861		dutch	Event Hopping 2 (JOI21_event2)	C++17	100 / 100	232 ms	24780 KiB

event2

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

const int Z = 2e5+2, B = 17, INF = 2e9;

int N, K, L[Z], R[Z];

int pR[Z][B], pL[Z][B];

set<array<int, 3>> intervals;

int solve(int i, int l, int r) {
	int j = i, res = 1;

	for(int k = B; k--; )
		if(pR[j][k] <= N && R[pR[j][k]] <= r)
			j = pR[j][k], res += 1<<k;

	j = i;
	for(int k = B; k--; )
		if(pL[j][k] >= 1 && l <= L[pL[j][k]])
			j = pL[j][k], res += 1<<k;

	return res;
}

int main() {
	ios::sync_with_stdio(0);
	cin.tie(0);

	cin >> N >> K;

	array<int, 2> pts[N * 2];

	for(int i = 1; i <= N; ++i) {
		cin >> L[i] >> R[i];
		--R[i];

		pts[2 * i - 1] = {L[i], -i};
		pts[2 * i - 2] = {R[i], +i};
	}

	L[N+1] = R[N+1] = INF;

	sort(pts, pts + N * 2);
	int j = 0;

	pL[0][0] = 0;
	pL[N+1][0] = max_element(L+1, L+N+1) - L;

	for(auto &[x, i] : pts) {
		if(i < 0)
			pL[-i][0] = j;
		else if(L[i] > L[j])
			j = i;
	}

	reverse(pts, pts + N * 2);
	j = N + 1;

	pR[0][0] = min_element(R+1, R+N+1) - R;
	pR[N+1][0] = N+1;

	for(auto &[x, i] : pts) {
		if(i > 0)
			pR[i][0] = j;
		else if(R[-i] < R[j])
			j = -i;
	}

	for(j = 0; j + 1 < B; ++j) {
		for(int i = 0; i <= N + 1; ++i) {
			pL[i][j+1] = pL[pL[i][j]][j];
			pR[i][j+1] = pR[pR[i][j]][j];
		}
	}

	int sum = solve(0, 0, INF - 1) - 1, req = K;

	if(sum < K) {
		cout << -1;
		return 0;
	}

	intervals.insert({L[0], 0, sum});
	intervals.insert({L[N+1], N+1, 0});

	for(int i = 1; i <= N && req; ++i) {
		auto fR = intervals.lower_bound({R[i] + 1});
		auto fL = prev(fR);

		if(R[(*fL)[1]] >= L[i]) continue;

		if(sum - (*fL)[2] + solve(i, R[(*fL)[1]]+1, (*fR)[0]-1) < K) continue;
		--req;

		array<int, 3> newL = *fL;
		newL[2] = solve((*fL)[1], (*fL)[0], L[i] - 1);

		int canDo = solve(i, L[i], (*fR)[0]-1);

		sum += newL[2] + canDo - (*fL)[2];

		intervals.erase(fL);
		intervals.insert(newL);
		intervals.insert({L[i], i, canDo});

		cout << i << '\n';
	}
}

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