Submission #316926

#	Time	Username	Problem	Language	Result	Execution time	Memory
316926		manh9203	Furniture (JOI20_furniture)	C++17	100 / 100	452 ms	24016 KiB

furniture

#include<bits/stdc++.h>
using namespace std;
using ll = long long;

const int N = 1005;

int n, m, q;
int a[N][N];
int dp[N][N][2], cntGood[2 * N];

bool check1(int x, int y) {
	if (dp[x][y][0] == 1 && dp[x - 1][y][0] == 0 && dp[x][y - 1][0] == 0) {
		return 1;
	} else {
		return 0;
	}
}
void dfs1(int x, int y) {
	if ((dp[x][y][0] & dp[x][y][1]) == 1) cntGood[x + y]--;
	dp[x][y][0] = 0;
	if (x + 1 <= n && check1(x + 1, y)) dfs1(x + 1, y);
	if (y + 1 <= m && check1(x, y + 1)) dfs1(x, y + 1);
}


bool check2(int x, int y) {
	if (dp[x][y][1] == 1 && dp[x + 1][y][1] == 0 && dp[x][y + 1][1] == 0) {
		return 1;
	} else {
		return 0;
	}
}
void dfs2(int x, int y) {
	if ((dp[x][y][0] & dp[x][y][1]) == 1) cntGood[x + y]--;
	dp[x][y][1] = 0;
	if (x - 1 >= 1 && check2(x - 1, y)) dfs2(x - 1, y);
	if (y - 1 >= 1 && check2(x, y - 1)) dfs2(x, y - 1);
}

int main() {
	ios_base::sync_with_stdio(0); cin.tie(0);

	cin >> n >> m;
	for (int i = 1; i <= n; i++) {
		for (int j = 1; j <= m; j++) {
			cin >> a[i][j];
		}
	}

	for (int i = 1; i <= n; i++) {
		for (int j = 1; j <= m; j++) {
			if (i == 1 && j == 1) {
				dp[i][j][0] = 1;
				continue;
			}
			if (a[i][j] == 0) dp[i][j][0] |= (dp[i - 1][j][0] | dp[i][j - 1][0]);
		}
	}
	for (int i = n; i >= 1; i--) {
		for (int j = m; j >= 1; j--) {
			if (i == n && j == m) {
				dp[i][j][1] = 1;
				continue;
			}
			if (a[i][j] == 0) dp[i][j][1] |= (dp[i + 1][j][1] | dp[i][j + 1][1]);
			if ((dp[i][j][0] & dp[i][j][1]) == 1) cntGood[i + j]++;
		}
	}

	cin >> q;
	while (q--) {
		int x, y; cin >> x >> y;
		if (a[x][y] == 1) {
			cout << 0 << "\n";
			continue;
		}
		if ((dp[x][y][0] & dp[x][y][1]) == 0) {
			a[x][y] = 1;
			cout << 1 << "\n";
			continue;
		}
		if (cntGood[x + y] == 1) {
			cout << 0 << "\n";
			continue;
		}
		a[x][y] = 1;
		dfs1(x, y); dfs2(x, y);
		cout << 1 << "\n";
	}
}

• Subtask 1: 5 / 5
• Subtask 2: 95 / 95