Submission #770977

#	Time	Username	Problem	Language	Result	Execution time	Memory
770977		SanguineChameleon	Comparing Plants (IOI20_plants)	C++17	100 / 100	644 ms	84832 KiB

plants

#include "plants.h"
#include <bits/stdc++.h>
using namespace std;

const int maxn = 2e5 + 20;
const int maxk = 20;
const int inf = 1e9 + 20;
int a[maxn];
int tree[maxn * 4];
int lazy[maxn * 4];
long long step_left[maxn][maxk];
long long step_right[maxn][maxk];
int height[maxn];
set<int> all_zeroes, good_zeroes;
int n, k;

void build(int id, int lt, int rt) {
	if (lt == rt) {
		tree[id] = a[lt];
		return;
	}
	int mt = (lt + rt) / 2;
	build(id * 2, lt, mt);
	build(id * 2 + 1, mt + 1, rt);
	tree[id] = min(tree[id * 2], tree[id * 2 + 1]);
}

void update(int id, int lt, int rt, int ql, int qr, int add) {
	if (lt == ql && rt == qr) {
		tree[id] += add;
		lazy[id] += add;
		return;
	}
	tree[id * 2] += lazy[id];
	lazy[id * 2] += lazy[id];
	tree[id * 2 + 1] += lazy[id];
	lazy[id * 2 + 1] += lazy[id];
	lazy[id] = 0;
	int mt = (lt + rt) / 2;
	if (qr <= mt) {
		update(id * 2, lt, mt, ql, qr, add);
	}
	else if (ql >= mt + 1) {
		update(id * 2 + 1, mt + 1, rt, ql, qr, add);
	}
	else {
		update(id * 2, lt, mt, ql, mt, add);
		update(id * 2 + 1, mt + 1, rt, mt + 1, qr, add);
	}
	tree[id] = min(tree[id * 2], tree[id * 2 + 1]);
}

bool contains(int x, int y) {
	if (x < y) {
		return y - x + 1 <= k;
	}
	else {
		return n - (x - y - 1) <= k;
	}
}

void add_zero(int x) {
	auto it = all_zeroes.insert(x).first;
	int prv = (it == all_zeroes.begin() ? *all_zeroes.rbegin() : *prev(it));
	if (!contains(prv, x)) {
		good_zeroes.insert(x);
	} 
	int nxt = (next(it) == all_zeroes.end() ? *all_zeroes.begin() : *next(it));
	if (contains(x, nxt)) {
		good_zeroes.erase(nxt);
	}
	else {
		good_zeroes.insert(nxt);
	}
}

void rem_zero(int x) {
	auto it = all_zeroes.find(x);
	int prv = (it == all_zeroes.begin() ? *all_zeroes.rbegin() : *prev(it));
	int nxt = (next(it) == all_zeroes.end() ? *all_zeroes.begin() : *next(it));
	if (contains(prv, nxt)) {
		good_zeroes.erase(nxt);
	}
	else {
		good_zeroes.insert(nxt);
	}
	int rt = x;
	int lt = (rt + n - (k - 1)) % n;
	if (lt <= rt) {
		update(1, 0, n - 1, lt, rt, -1);
	}
	else {
		update(1, 0, n - 1, lt, n - 1, -1);
		update(1, 0, n - 1, 0, rt, -1);
	}
	all_zeroes.erase(it);
	good_zeroes.erase(x);
}

void find_zeroes(int id, int lt, int rt) {
	if (tree[id] > 0) {
		return;
	}
	if (lt == rt) {
		add_zero(lt);
		tree[id] = inf;
		lazy[id] = 0;
		return;
	}
	tree[id * 2] += lazy[id];
	lazy[id * 2] += lazy[id];
	tree[id * 2 + 1] += lazy[id];
	lazy[id * 2 + 1] += lazy[id];
	lazy[id] = 0;
	int mt = (lt + rt) / 2;
	find_zeroes(id * 2, lt, mt);
	find_zeroes(id * 2 + 1, mt + 1, rt);
	tree[id] = min(tree[id * 2], tree[id * 2 + 1]);
}

int dist_right(int x, int y) {
	return (y + n - x) % n;
}

int dist_left(int x, int y) {
	return (x + n - y) % n;
}

void init(int _k, vector<int> _a) {
	n = _a.size();
	k = _k;
	for (int i = 0; i < n; i++) {
		a[i] = _a[i];
	}
	build(1, 0, n - 1);
	for (int i = n - 1; i >= 0; i--) {
		find_zeroes(1, 0, n - 1);
		height[*good_zeroes.begin()] = i;
		rem_zero(*good_zeroes.begin());
	}
	set<pair<int, int>> heights;
	for (int i = 0; i < k - 1; i++) {
		heights.emplace(height[i], i);
	}
	for (int i = 0; i < n; i++) {
		int prv = (i + n - 1) % n;
		int nxt = (i + k - 1) % n;
		auto it = heights.upper_bound(make_pair(height[prv], -1));
		step_right[prv][0] = (it == heights.end() ? 0 : dist_right(prv, it->second));
		it = heights.upper_bound(make_pair(height[nxt], -1));
		step_left[nxt][0] = (it == heights.end() ? 0 : dist_left(nxt, it->second));
		heights.erase(make_pair(height[i], i));
		heights.emplace(height[nxt], nxt);
	}
	for (int k = 1; k < maxk; k++) {
		for (int i = 0; i < n; i++) {
			step_right[i][k] = step_right[i][k - 1] + step_right[(step_right[i][k - 1] + i) % n][k - 1];
			step_left[i][k] = step_left[i][k - 1] + step_left[(n - step_left[i][k - 1] % n + i) % n][k - 1];
		}
	}
	return;
}

int check_left(int x, int y) {
	int dist = dist_left(x, y);
	for (int k = maxk - 1; k >= 0; k--) {
		if (step_left[x][k] < dist) {
			dist -= step_left[x][k];
			x = (x + n - step_left[x][k] % n) % n;
		}
	}
	return dist < k && height[x] < height[y];
}

int check_right(int x, int y) {
	int dist = dist_right(x, y);
	for (int k = maxk - 1; k >= 0; k--) {
		if (step_right[x][k] < dist) {
			dist -= step_right[x][k];
			x = (x + step_right[x][k]) % n;
		}
	}
	return dist < k && height[x] < height[y];
}

int compare_plants(int x, int y) {
	if (check_left(x, y) || check_right(x, y)) {
		return -1;
	}
	else if (check_left(y, x) || check_right(y, x)) {
		return 1;
	}
	else {
		return 0;
	}
}

• Subtask 1: 5 / 5
• Subtask 2: 14 / 14
• Subtask 3: 13 / 13
• Subtask 4: 17 / 17
• Subtask 5: 11 / 11
• Subtask 6: 15 / 15
• Subtask 7: 25 / 25