Submission #197743

#	Time	Username	Problem	Language	Result	Execution time	Memory
197743		Minnakhmetov	Rectangles (IOI19_rect)	C++14	13 / 100	766 ms	354772 KiB

rect

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

#define ll long long

const int N = 2505;
int dx[4] = {-1, 1, 0, 0},
	dy[4] = {0, 0, -1, 1};
bool used[N][N];
int mn_x, mx_x, mn_y, mx_y, ct, n, m;

void dfs(vector<vector<int>> &a, int x, int y) {
	used[x][y] = 1;
	ct++;

	mn_x = min(mn_x, x);
	mx_x = max(mx_x, x);

	mn_y = min(mn_y, y);
	mx_y = max(mx_y, y);

	for (int i = 0; i < 4; i++) {
		int p = x + dx[i],
			q = y + dy[i];
		if (p >= 0 && p < n && q >= 0 && q < m && 
			a[p][q] == 0 && !used[p][q]) {
			dfs(a, p, q);
		}
	}
}

bool check(vector<vector<int>> &a, int xl, int xr, int yl, int yr) {
	for (int i = xl; i <= xr; i++) {
		for (int j = yl; j <= yr; j++) {
			if (a[i][j] >= a[i][yl - 1] ||
				a[i][j] >= a[i][yr + 1] ||
				a[i][j] >= a[xl - 1][j] ||
				a[i][j] >= a[xr + 1][j]) {
				return false;
			}
		}
	}	
	return true;
}

ll solve_slow(vector<vector<int>> a) {
	n = a.size();
	m = a[0].size();
 
	ll ans = 0;
 
	for (int xl = 1; xl < n - 1; xl++) {
		for (int yl = 1; yl < m - 1; yl++) {
			for (int xr = xl; xr < n - 1; xr++) {
				for (int yr = yl; yr < m - 1; yr++) {
					if (check(a, xl, xr, yl, yr))
						ans++;
				}
			}
		}
	}
 
	return ans;
}

ll solve01(vector<vector<int>> a) {
	n = a.size();
	m = a[0].size();

	ll ans = 0;

	for (int i = 0; i < n; i++) {
		for (int j = 0; j < m; j++) {
			if (!used[i][j] && a[i][j] == 0) {
				mn_x = N, mx_x = -1, mn_y = N, mx_y = -1, ct = 0;

				dfs(a, i, j);

				if (mn_x > 0 && mx_x < n - 1 &&
					mn_y > 0 && mx_y < m - 1 &&
					ct == (mx_x - mn_x + 1) * (mx_y - mn_y + 1)) {
					ans++;
				}
			}
		}
	}

	return ans;
}

ll count_rectangles(vector<vector<int>> a) {
	return solve01(a);
}

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