Submission #740551

#	Time	Username	Problem	Language	Result	Execution time	Memory
740551		alex_2008	송신탑 (IOI22_towers)	C++17	58 / 100	1152 ms	27428 KiB

towers

#include "towers.h"
#include <iostream>
#include <vector>
#include <cmath>
#include <set>
#include <algorithm>
using namespace std;
int ind = -1;
bool ch = true;
vector <int> h;
const int N = 100100, M = 20;
int mx[N][M], Left[N], Right[N], pref[N], LS[N], RS[N];
int mxleft[N][M], mnright[N][M];
vector <int> esim;
vector <int> indexes;
bool check = true;
int findmaxinrange(int L, int R) {
	if (L > R) return 0;
	int u = log2(R - L + 1);
	return max(mx[L][u], mx[R - (1 << u) + 1][u]);
}
int findmininrange(int L, int R, int w) {
	if (L > R) return 2e9 + 1;
	int u = log2(R - L + 1);
	if (w == 1) return max(mxleft[L][u], mxleft[R - (1 << u) + 1][u]);
	return min(mnright[L][u], mnright[R - (1 << u) + 1][u]);
}
void init(int n, vector<int> a) {
	ch = true;
	ind = -1;
	h = a;
	pref[0] = 0;
	for (int i = 0; i < n - 1; ++i)
	{
		if (a[i] > a[i + 1]) {
			if (ind == -1) ind = i;
		}
		else {
			if (ind != -1) ch = false;
		}
	}
	LS[0] = -1;
	RS[n - 1] = -1;
	for (int i = 1; i < n; i++) {
		int v = i - 1;
		while (v != -1 && a[i] < a[v]) {
			v = LS[v];
		}
		LS[i] = v;
	}
	for (int i = n - 2; i >= 0; i--) {
		int v = i + 1;
		while (v != -1 && a[i] < a[v]) {
			v = RS[v];
		}
		RS[i] = v;
	}
	for (int i = 1; i < n - 1; i++) {
		pref[i] = pref[i - 1];
		if (a[i] < a[i + 1] && a[i] < a[i - 1]) pref[i]++;
	}
	for (int i = 0; i < n; i++) {
		mx[i][0] = a[i];
	}
	for (int j = 1; j < 20; j++) {
		for (int i = n - 1; i >= 0; i--) {
			mx[i][j] = max(mx[i][j - 1], mx[min(n - 1, i + (1 << (j - 1)))][j - 1]);
		}
	}
	for (int i = 0; i < n; i++) {
		int hmn = 2e9;
		if (LS[i] != -1) {
			hmn = min(hmn, findmaxinrange(LS[i] + 1, i - 1));
		}
		if (RS[i] != -1) {
			hmn = min(hmn, findmaxinrange(i + 1, RS[i] - 1));
		}
		int u = hmn - a[i];
		esim.push_back(u);
	}
	sort(esim.begin(), esim.end());
}
int querynumber = 0;
int max_towers(int L, int R, int D) {
	int n = (int)h.size();
	++querynumber;
	if (ch) {
		if (R < ind || L > ind) return 1;
		if (h[ind] >= (max(h[L], h[R]) + D)) return 2;
		return 1;
	}
	if (querynumber == 1) {
		vector <pair<int, int>> v;
		set <int> ms;
		for (int i = 0; i < n; i++) {
			int l = 0, r = i - 1;
			Left[i] = -1;
			while (l <= r) {
				int mid = (l + r) / 2;
				if (findmaxinrange(mid, i - 1) >= h[i] + D) {
					Left[i] = mid;
					l = mid + 1;
				}
				else r = mid - 1;
			}
			Right[i] = n;
			l = i + 1, r = n - 1;
			while (l <= r) {
				int mid = (l + r) / 2;
				if (findmaxinrange(i + 1, mid) >= h[i] + D) {
					Right[i] = mid;
					r = mid - 1;
				}
				else l = mid + 1;
			}
			v.push_back({ h[i], i });
		}
		int ans = 0;
		sort(v.begin(), v.end());
		for (auto q : v) {
			int ind = q.second;
			if (ind > R || ind < L) continue;
			auto it = ms.lower_bound(ind);
			if (it != ms.begin()) {
				it--;
				if (*it > Left[ind]) continue;
			}
			it = ms.lower_bound(ind);
			if (it != ms.end() && *it < Right[ind]) {
				continue;
			}
			ms.insert(ind);
			++ans;
		}
		return ans;
	}
	if (D == 1) {
		if (L == R) {
			return 1;
		}
		int cnt = pref[R - 1] - pref[L];
		if (h[L] < h[L + 1]) ++cnt;
		if (h[R] < h[R - 1]) ++cnt;
		return cnt;
	}
	if (L == 0 && R == n - 1) {
		int u = lower_bound(esim.begin(), esim.end(), D) - esim.begin();
		return n - u;
	}
	if (check) {
		check = false;
		vector <pair<int, int>> v;
		set <int> ms;
		for (int i = 0; i < n; i++) {
			int l = 0, r = i - 1;
			Left[i] = -1;
			while (l <= r) {
				int mid = (l + r) / 2;
				if (findmaxinrange(mid, i - 1) >= h[i] + D) {
					Left[i] = mid;
					l = mid + 1;
				}
				else r = mid - 1;
			}
			Right[i] = n;
			l = i + 1, r = n - 1;
			while (l <= r) {
				int mid = (l + r) / 2;
				if (findmaxinrange(i + 1, mid) >= h[i] + D) {
					Right[i] = mid;
					r = mid - 1;
				}
				else l = mid + 1;
			}
		}
		for (int i = 0; i < n; i++) {
			int hmn = 2e9;
			if (LS[i] != -1) {
				hmn = min(hmn, findmaxinrange(LS[i] + 1, i - 1));
			}
			if (RS[i] != -1) {
				hmn = min(hmn, findmaxinrange(i + 1, RS[i] - 1));
			}
			int u = hmn - h[i];
			if (u >= D) {
				indexes.push_back(i);
			}
		}
		for (int i = 0; i < n; i++) {
			mxleft[i][0] = Left[i];
			mnright[i][0] = Right[i];
		}
		for (int j = 1; j < 20; j++) {
			for (int i = n - 1; i >= 0; i--) {
				mxleft[i][j] = max(mxleft[i][j - 1], mxleft[min(n - 1, i + (1 << (j - 1)))][j - 1]);
				mnright[i][j] = min(mnright[i][j - 1], mnright[min(n - 1, i + (1 << (j - 1)))][j - 1]);
			}
		}
	}
	if (L == R) {
		return 1;
	}
	auto it = lower_bound(indexes.begin(), indexes.end(), L);
	int ans = upper_bound(indexes.begin(), indexes.end(), R) - lower_bound(indexes.begin(), indexes.end(), L);
	if (it != indexes.end()) {
		int q = Left[*it];
		if (L < q) {
			if (findmininrange(L, q - 1, 2) < *it) {
				++ans;
			}
		}
	}
	it = upper_bound(indexes.begin(), indexes.end(), R);
	if (it != indexes.begin()) {
		--it;
		int q = Right[*it];
		if (q < R) {
			if (findmininrange(q + 1, R, 1) > *it) {
				++ans;
			}
		}
	}
	return ans;
}

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