Submission #758493

#	Time	Username	Problem	Language	Result	Execution time	Memory
758493		rainboy	Sequence (APIO23_sequence)	C++17	50 / 100	2087 ms	32708 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], 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] = min(pp[l], ss[l] + pp[r]);
	qq[i] = min(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] = min(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] = min(x, 0);
	while (i > 1)
		pul(ss, pp, qq, i >>= 1);
}

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

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

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

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;
	}
}

bool solve(int k) {
	build(ss1, pp1, qq1, 1), build(ss2, pp2, qq2, -1);
	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);
		}
		for (int h = i; h + k <= j; h++) {
			int l = ii[h], r = ii[h + k - 1], s;
			if ((s = query_s(ss1, l, r)) > 0) {
				if (query_q(ss1, qq1, l - 1) + s + query_p(ss1, pp1, r + 1) <= 0)
					return true;
			} else if ((s = query_s(ss2, l, r)) > 0) {
				if (query_q(ss2, qq2, l - 1) + s + query_p(ss2, pp2, r + 1) <= 0)
					return true;
			} else
				return true;
		}
		for (int h = i; h < j; h++) {
			int i_ = ii[h];
			update(ss2, pp2, qq2, i_, 1);
		}
	}
	return false;
}

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);
	int lower = 0, upper = n + 1;
	while (upper - lower > 1) {
		int k = (lower + upper) / 2;
		if (solve(k))
			lower = k;
		else
			upper = k;
	}
  return lower;
}

• Subtask 1: 11 / 11
• Subtask 2: 17 / 17
• Subtask 3: 0 / 7
• Subtask 4: 0 / 12
• Subtask 5: 0 / 13
• Subtask 6: 22 / 22
• Subtask 7: 0 / 18