Submission #631064

#	Time	Username	Problem	Language	Result	Execution time	Memory
631064		rainboy	Radio Towers (IOI22_towers)	C++17	18 / 100	1158 ms	4184 KiB

towers

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

using namespace std;

const int N = 100000;

int abs_(int a) { return a > 0 ? a : -a; }
int max(int a, int b) { return a > b ? a : b; }

typedef vector<int> vi;

int dd[N], iq[N + 1], pq[N], cnt;

int lt(int i, int j) { return dd[i] < dd[j]; }

int p2(int p) {
	return (p *= 2) > cnt ? 0 : (p < cnt && lt(iq[p + 1], iq[p]) ? p + 1 : p);
}

void pq_up(int i) {
	int p, q, j;
	for (p = pq[i]; (q = p / 2) && lt(i, j = iq[q]); p = q)
		iq[pq[j] = p] = j;
	iq[pq[i] = p] = i;
}

void pq_dn(int i) {
	int p, q, j;
	for (p = pq[i]; (q = p2(p)) && lt(j = iq[q], i); p = q)
		iq[pq[j] = p] = j;
	iq[pq[i] = p] = i;
}

void pq_add(int i) {
	pq[i] = ++cnt, pq_up(i);
}

int pq_remove_first() {
	int i = iq[1], j = iq[cnt--];
	if (j != i)
		pq[j] = 1, pq_dn(j);
	pq[i] = 0;
	return i;
}

void pq_remove(int i) {
	int j = iq[cnt--];
	if (j != i)
		pq[j] = pq[i], pq_up(j), pq_dn(j);
	pq[i] = 0;
}

int aa[N], ii[N], ii_[N], ll[N], rr[N], pp[N], qq[N], n, p, k, k_, first;

void init(int n_, vi aa_) {
	n = n_;
	for (int i = 0; i < n; i++)
		aa[i] = aa_[i];
	p = 0;
	while (p < n - 1 && aa[p] < aa[p + 1])
		p++;
	for (int i = p + 1; i < n; i++)
		if (aa[i - 1] < aa[i]) {
			p = -1;
			break;
		}
	first = 1;
	k = 0;
	ii[k++] = 0;
	for (int i = 1; i < n; i++)
		if (k % 2 != 0) {
			if (aa[ii[k - 1]] > aa[i])
				ii[k - 1] = i;
			else
				ii[k++] = i;
		} else {
			if (aa[ii[k - 1]] < aa[i])
				ii[k - 1] = i;
			else
				ii[k++] = i;
		}
	if (k % 2 == 0)
		k--;
	for (int h = 0; h < k; h++)
		pp[ii[h]] = h == 0 ? -1 : ii[h - 1], qq[ii[h]] = h + 1 == k ? n : ii[h + 1];
	for (int h = 0; h + 1 < k; h++)
		dd[ii[h]] = abs_(aa[ii[h + 1]] - aa[ii[h]]), pq_add(ii[h]);
	k = 0;
	while (cnt) {
		int i = pq_remove_first(), j = qq[i];
		if (pp[i] == -1)
			pq_remove(j);
		else if (qq[j] == n)
			pq_remove(pp[i]);
		else {
			pq_remove(pp[i]), pq_remove(j);
			dd[pp[i]] = abs_(aa[qq[j]] - aa[pp[i]]), pq_add(pp[i]);
		}
		if (aa[i] > aa[j])
			ii[k++] = i;
		else
			dd[j] = dd[i], ii[k++] = j;
	}
}

int max_towers(int l, int r, int d) {
	if (p != -1)
		return l < p && p < r && aa[p] - aa[l] >= d && aa[p] - aa[r] >= d ? 2 : 1;
	else if (l == 0 && r == n - 1) {
		int lower = -1, upper = k;
		while (upper - lower > 1) {
			int h = (lower + upper) / 2;
			if (dd[ii[h]] < d)
				lower = h;
			else
				upper = h;
		}
		return k - upper + 1;
	} else {
		if (first) {
			k_ = 0;
			ii_[k_++] = 0;
			for (int i = 1; i < n; i++)
				if (k_ % 2 != 0) {
					if (aa[ii_[k_ - 1]] > aa[i])
						ii_[k_ - 1] = i;
					else if (aa[i] - aa[ii_[k_ - 1]] >= d)
						ii_[k_++] = i;
				} else {
					if (aa[ii_[k_ - 1]] < aa[i])
						ii_[k_ - 1] = i;
					else if (aa[ii_[k_ - 1]] - aa[i] >= d)
						ii_[k_++] = i;
				}
			for (int h = 1; h < k_ - 1; h += 2) {
				for (int i = ii_[h] - 1; i >= 0; i--)
					if (aa[ii_[h]] - aa[i] >= d) {
						ll[h / 2] = i;
						break;
					}
				for (int i = ii_[h] + 1; i < n; i++)
					if (aa[ii_[h]] - aa[i] >= d) {
						rr[h / 2] = i;
						break;
					}
			}
			k_ = (k_ - 1) / 2;
			first = 0;
		}
		int lower, upper;
		lower = -1, upper = k_;
		while (upper - lower > 1) {
			int h = (lower + upper) / 2;
			if (l <= ll[h])
				upper = h;
			else
				lower = h;
		}
		l = upper;
		lower = -1, upper = k_;
		while (upper - lower > 1) {
			int h = (lower + upper) / 2;
			if (rr[h] <= r)
				lower = h;
			else
				upper = h;
		}
		r = lower;
		return max(r - l + 1, 0) + 1;
	}
}

• Subtask 1: 4 / 4
• Subtask 2: 0 / 11
• Subtask 3: 0 / 12
• Subtask 4: 14 / 14
• Subtask 5: 0 / 17
• Subtask 6: 0 / 19
• Subtask 7: 0 / 23