Submission #1068020

#	Time	Username	Problem	Language	Result	Execution time	Memory
1068020		Gromp15	Rectangles (IOI19_rect)	C++17	59 / 100	1606 ms	73468 KiB

rect

#include <bits/stdc++.h>
#pragma GCC optimize("O3")
#pragma GCC target("avx2")
#include "rect.h"
#define ll long long
#define ar array
#define all(x) x.begin(), x.end()
#define sz(x) (int)x.size()
using namespace std;
template<typename T> bool ckmin(T &a, const T &b) { return a > b ? a = b, 1 : 0; }
template<typename T> bool ckmax(T &a, const T &b) { return a < b ? a = b, 1 : 0; }

using namespace std;
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
#define rint(l, r) uniform_int_distribution<int>(l, r)(rng)

struct fenwick {
	int n; vector<int> bit;
	fenwick(int a) : n(a), bit(a+1) {}
	void update(int pos, int x) {
		pos++;
		for (int i = pos; i <= n; i += i&-i) bit[i] += x;
	}
	int sum(int pos) {
		int res = 0;
		while (pos) res += bit[pos], pos -= pos&-pos;
		return res;
	}
	int query(int l, int r) {
		return sum(r+1) - sum(l);
	}
};

long long count_rectangles(std::vector<std::vector<int>> a) {
	int n = sz(a), m = sz(a[0]);
	if ((n <= 700 && m <= 700) || (n <= 3)) {
		vector ok(n, vector(n, vector<bool>(m)));
		for (int i = 0; i < m; i++) {
			for (int j = 1; j < n-1; j++) {
				int mx = 0;
				for (int k = j; k < n-1; k++) {
					ckmax(mx, a[k][i]);
					ok[j][k][i] = mx >= min(a[j-1][i], a[k+1][i]);
				}
			}
		}
		vector<vector<int>> right(n, vector<int>(m, -1)), left(n, vector<int>(m, m-1));
		for (int i = 0; i < n; i++) {
			for (int j = 1; j < m-1; j++) {
				int mx = 0;
				for (int k = j; k < m-1; k++) {
					ckmax(mx, a[i][k]);
					if (mx >= a[i][j-1]) break;
					right[i][j] = k;
				}
			}
			for (int j = m-2; j >= 1; j--) {
				int mx = 0;
				for (int k = j; k >= 1; k--) {
					ckmax(mx, a[i][k]);
					if (mx >= a[i][j+1]) break;
					left[i][j] = k;
				}
			}
		}
		long long ans = 0;
		for (int i = 1; i < n-1; i++) { 
			vector<int> R(m, m-2), L(m, -1);
			for (int j = i; j < n-1; j++) {
				for (int k = 0; k < m; k++) {
					ckmin(R[k], right[j][k]);
					ckmax(L[k], left[j][k]);
				}
				vector<int> to(m, -1);
				for (int k = m-1; k >= 0; k--) if (!ok[i][j][k]) {
					int l = k;
					while (l && !ok[i][j][l-1]) l--;
					for (int z = l; z <= k; z++) to[z] = k;
					k = l;
				}
				for (int k = 1; k < m-1; k++) {
					int r = min(to[k], R[k]);
					for (int l = k; l <= r; l++) ans += L[l] <= k;
				}
			}
		}
		return ans;
	}
	vector<vector<int>> to(n, vector<int>(m));
	for (int i = 1; i < m-1; i++) {
		for (int j = n-2; j > 0; j--) if (!a[j][i]) {
			int l = j;
			while (l-1 > 0 && !a[l-1][i]) l--;
			for (int k = l; k <= j; k++) to[k][i] = j;
			j = l;
		}
	}
	int ans = 0;
	for (int i = 0; i < n; i++) {
		vector<int> l(m), r(m, m-1);
		vector<int> st;
		for (int j = 0; j < m; j++) {
			while (st.size() && to[i][st.back()] >= to[i][j]) st.pop_back();
			if (st.size()) l[j] = st.back();
			st.emplace_back(j);
		}
		st.clear();
		for (int j = m-1; j >= 0; j--) {
			while (st.size() && to[i][st.back()] >= to[i][j]) st.pop_back();
			if (st.size()) r[j] = st.back();
			st.emplace_back(j);
		}
		for (int j = 0; j < m-1; j++) if (l[j] <= j && j <= r[j]) {
			ckmax(ans, (to[i][j] - i + 1) * (r[j] - l[j] - 1));
		}
	}
	return ans;
}

• Subtask 1: 8 / 8
• Subtask 2: 7 / 7
• Subtask 3: 12 / 12
• Subtask 4: 22 / 22
• Subtask 5: 10 / 10
• Subtask 6: 0 / 13
• Subtask 7: 0 / 28