Submission #758503

#	Time	Username	Problem	Language	Result	Execution time	Memory
758503		rainboy	Sequence (APIO23_sequence)	C++17	100 / 100	698 ms	36752 KiB

sequence

#include "sequence.h"
#include <vector>

using namespace std;

typedef vector<int> vi;

const int N = 500000, N_ = 1 << 19;	/* N_ = pow2(ceil(log2(N + 1))) */

unsigned int X = 12345;

int rand_() {
	return (X *= 3) >> 1;
}

int aa[N], ii[N], pp[N], qq[N], n;
int ss1[N_ * 2], pp1[N_ * 2], qq1[N_ * 2], ss2[N_ * 2], pp2[N_ * 2], qq2[N_ * 2], n_;

void pul(int *ss, int *pp, int *qq, int i) {
	int l = i << 1, r = l | 1;
	ss[i] = ss[l] + ss[r];
	pp[i] = max(pp[l], ss[l] + pp[r]);
	qq[i] = max(qq[l] + ss[r], qq[r]);
}

void build(int *ss, int *pp, int *qq, int x) {
	for (int i = 0; i < n_; i++)
		ss[n_ + i] = i < n ? x : 0, pp[n_ + i] = qq[n_ + i] = max(ss[n_ + i], 0);
	for (int i = n_ - 1; i > 0; i--)
		pul(ss, pp, qq, i);
}

void update(int *ss, int *pp, int *qq, int i, int x) {
	i += n_;
	ss[i] = x, pp[i] = qq[i] = max(x, 0);
	while (i > 1)
		pul(ss, pp, qq, i >>= 1);
}

int query_p(int *ss, int *pp, int r) {
	int l = 0, p = 0;
	for (l += n_, r += n_; l <= r; l >>= 1, r >>= 1)
		if ((r & 1) == 0)
			p = max(pp[r], ss[r] + p), r--;
	return p;
}

int query_q(int *ss, int *qq, int l) {
	int r = n_ - 1, q = 0;
	for (l += n_, r += n_; l <= r; l >>= 1, r >>= 1)
		if ((l & 1) == 1)
			q = max(q + ss[l], qq[l]), l++;
	return q;
}

void sort(int *ii, int l, int r) {
	while (l < r) {
		int i = l, j = l, k = r, i_ = ii[l + rand_() % (r - l)], tmp;
		while (j < k) {
			int c = aa[ii[j]] != aa[i_] ? aa[ii[j]] - aa[i_] : ii[j] - i_;

			if (c == 0)
				j++;
			else if (c < 0) {
				tmp = ii[i], ii[i] = ii[j], ii[j] = tmp;
				i++, j++;
			} else {
				k--;
				tmp = ii[j], ii[j] = ii[k], ii[k] = tmp;
			}
		}
		sort(ii, l, i);
		l = k;
	}
}

int sequence(int n1, vi aa_) {
	n = n1;
	n_ = 1;
	while (n_ <= n)
		n_ <<= 1;
	for (int i = 0; i < n; i++) {
		aa[i] = aa_[i];
		ii[i] = i;
	}
	sort(ii, 0, n);
	build(ss1, pp1, qq1, 1), build(ss2, pp2, qq2, -1);
	int ans = 0;
	for (int i = 0, j; i < n; i = j) {
		j = i + 1;
		while (j < n && aa[ii[j]] == aa[ii[i]])
			j++;
		for (int h = i; h < j; h++) {
			int i_ = ii[h];
			update(ss1, pp1, qq1, i_, -1);
		}
		if (j * 2 < n) {
			for (int h = i; h < j; h++)
				pp[h] = query_p(ss1, pp1, ii[h] - 1);
			for (int h = i; h < j; h++)
				qq[h] = query_q(ss1, qq1, ii[h] + 1);
			for (int h = i, h_ = i; h < j; h++) {
				while (h_ < j && pp[h] + qq[h_] >= n - j * 2)
					h_++;
				ans = max(ans, h_ - h);
			}
		} else if (i * 2 > n) {
			for (int h = i; h < j; h++)
				pp[h] = query_p(ss2, pp2, ii[h] - 1);
			for (int h = i; h < j; h++)
				qq[h] = query_q(ss2, qq2, ii[h] + 1);
			for (int h = i, h_ = i; h < j; h++) {
				while (h_ < j && pp[h] + qq[h_] >= i * 2 - n)
					h_++;
				ans = max(ans, h_ - h);
			}
		} else
			ans = max(ans, j - i);
		for (int h = i; h < j; h++) {
			int i_ = ii[h];
			update(ss2, pp2, qq2, i_, 1);
		}
	}
	return ans;
}

• Subtask 1: 11 / 11
• Subtask 2: 17 / 17
• Subtask 3: 7 / 7
• Subtask 4: 12 / 12
• Subtask 5: 13 / 13
• Subtask 6: 22 / 22
• Subtask 7: 18 / 18