Submission #291794

#	Time	Username	Problem	Language	Result	Execution time	Memory
291794		keko37	Rectangles (IOI19_rect)	C++14	0 / 100	79 ms	53624 KiB

rect

#include<bits/stdc++.h>
#include "rect.h"

using namespace std;

typedef long long llint;
typedef pair <int, int> pi;

const int MAXN = 705;
const int INF = 1000000007;

int n, m, curr, sol;
int a[MAXN][MAXN], mn[MAXN];
int lef[MAXN][MAXN], rig[MAXN][MAXN];
vector <pi> v[MAXN];
int ok[MAXN], cnt[MAXN][MAXN];

void precompute_row (int r) {
	vector <int> st;
	for (int c = 0; c < m; c++) {
		while (!st.empty() && a[r][st.back()] < a[r][c]) st.pop_back();
		lef[r][c] = (st.empty() ? -1 : st.back());
		st.push_back(c);
		if (lef[r][c] != -1 && lef[r][c] != c - 1) v[r].push_back({lef[r][c] + 1, c - 1});
	}
	st.clear();
	for (int c = m - 1; c >= 0; c--) {
		while (!st.empty() && a[r][st.back()] < a[r][c]) st.pop_back();
		rig[r][c] = (st.empty() ? -1 : st.back());
		st.push_back(c);
		if (rig[r][c] != -1 && rig[r][c] != c + 1) v[r].push_back({c + 1, rig[r][c] - 1});
	}
	sort(v[r].begin(), v[r].end());
	v[r].erase(unique(v[r].begin(), v[r].end()), v[r].end());
}

inline int sum (int a, int b) {
	if (a == 0) return ok[b];
	return ok[b] - ok[a - 1];
}

void add_row (int r) {
	for (auto par : v[r]) {
		int a = par.first, b = par.second;
		cnt[a][b]++;
		if (cnt[a][b] == curr && sum(a, b) == 0) sol++;
	}
}

llint count_rectangles (vector<vector<int>> A) {
	n = A.size(), m = A[0].size();
	for (int i = 0; i < n; i++) {
		for (int j = 0; j < m; j++) {
			a[i][j] = A[i][j];
		}
	}
	for (int r = 0; r < n; r++) precompute_row(r);
	for (int r1 = 0; r1 < n; r1++) {
		memset(cnt, 0, sizeof cnt);
		curr = 0;
		for (int c = 0; c < m; c++) {
			mn[c] = INF;
		}
		for (int r2 = r1 + 2; r2 < n; r2++) {
			for (int c = 0; c < m; c++) {
				mn[c] = min(mn[c], a[r2 - 1][c]);
				if (mn[c] < a[r1][c] && mn[c] < a[r2][c]) ok[c] = 0; else ok[c] = 1;
				if (c > 0) ok[c] += ok[c - 1];
			}
			curr++;
			add_row(r2 - 1);
		}
	}
	return sol;
}

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