Submission #631079

#	Time	Username	Problem	Language	Result	Execution time	Memory
631079		rainboy	Radio Towers (IOI22_towers)	C++17	100 / 100	1632 ms	22300 KiB

towers

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

using namespace std;

const int N = 100000, L = 17, N_ = 1 << L, N1 = 1 + N * (L + 1), INF = 0x3f3f3f3f;	/* L = ceil(log2(N)) */

int abs_(int a) { return a > 0 ? a : -a; }
int min(int a, int b) { return a < b ? a : b; }
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 st[N_ * 2], n_;

int query(int l, int r) {
	int x = INF;
	for (l += n_, r += n_; l <= r; l >>= 1, r >>= 1) {
		if ((l & 1) == 1)
			x = min(x, st[l++]);
		if ((r & 1) == 0)
			x = min(x, st[r--]);
	}
	return x;
}

int kk[N1], ll[N1], rr[N1], mn[N1], mx[N1], _ = 1;

int update_(int t, int l, int r, int i) {
	int t_ = _++;
	ll[t_] = ll[t], rr[t_] = rr[t], kk[t_] = kk[t] + 1, mn[t_] = min(mn[t], i), mx[t_] = max(mx[t], i);
	if (r - l > 1) {
		int m = (l + r) / 2;
		if (i < m)
			ll[t_] = update_(ll[t], l, m, i);
		else
			rr[t_] = update_(rr[t], m, r, i);
	}
	return t_;
}

int mn_, mx_, k_;

void query_(int t, int l, int r, int ql, int qr) {
	if (t == 0 || qr <= l || r <= ql)
		return;
	if (ql <= l && r <= qr) {
		mn_ = min(mn_, mn[t]), mx_ = max(mx_, mx[t]), k_ += kk[t];
		return;
	}
	int m = (l + r) / 2;
	query_(ll[t], l, m, ql, qr), query_(rr[t], m, r, ql, qr);
}

int aa[N], ii[N], tt[N + 1], pp[N], qq[N], n, k;

void init(int n1, vi aa_) {
	n = n1;
	for (int i = 0; i < n; i++)
		aa[i] = aa_[i];
	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]);
	mn[0] = INF, mx[0] = -1;
	k = 0;
	while (cnt) {
		int i = pq_remove_first(), j = qq[i], tmp;
		if (pp[i] == -1) {
			pq_remove(j);
			pp[qq[j]] = -1;
		} else if (qq[j] == n) {
			pq_remove(pp[i]);
			qq[pp[i]] = n;
		} else {
			pq_remove(pp[i]), pq_remove(j);
			qq[pp[i]] = qq[j], pp[qq[j]] = pp[i];
			dd[pp[i]] = abs_(aa[qq[j]] - aa[pp[i]]), pq_add(pp[i]);
		}
		if (aa[i] < aa[j]) {
			tmp = i, i = j, j = tmp;
			dd[i] = dd[j];
		}
		ii[k++] = i;
	}
	for (int h = k - 1; h >= 0; h--)
		tt[h] = update_(tt[h + 1], 0, n, ii[h]);
	n_ = 1;
	while (n_ < n)
		n_ <<= 1;
	for (int i = 0; i < n; i++)
		st[n_ + i] = aa[i];
	for (int i = n_ - 1; i > 0; i--)
		st[i] = min(st[i << 1 | 0], st[i << 1 | 1]);
}

int max_towers(int l, int r, int d) {
	int lower = -1, upper = k;
	while (upper - lower > 1) {
		int h = (lower + upper) / 2;
		if (dd[ii[h]] < d)
			lower = h;
		else
			upper = h;
	}
	mn_ = INF, mx_ = -1, k_ = 0;
	query_(tt[upper], 0, n, l, r);
	if (k_ == 0)
		return 1;
	else if (k_ == 1)
		return aa[mn_] - query(l, mn_) >= d && aa[mx_] - query(mx_, r) >= d ? 2 : 1;
	else
		return k_ - (aa[mn_] - query(l, mn_) >= d ? 0 : 1) - (aa[mx_] - query(mx_, r) >= d ? 0 : 1) + 1;
}

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