Submission #716294

#	Time	Username	Problem	Language	Result	Execution time	Memory
716294		rainboy	Furniture (JOI20_furniture)	C11	100 / 100	393 ms	15860 KiB

furniture

#include <stdio.h>

#define N	1000
#define M	1000

int di[] = { -1, 1, 0, 0 };
int dj[] = { 0, 0, -1, 1 };

int cc[N][M], kk[N + M], n, m;

void dfs(int i, int j) {
	int h, i_, j_, b;

	if (i == 0 && j == 0 || i == n - 1 && j == m - 1)
		return;
	b = 0;
	for (h = 0; h < 4; h++) {
		i_ = i + di[h], j_ = j + dj[h];
		if (i_ >= 0 && i_ < n && j_ >= 0 && j_ < m && cc[i_][j_] == 0)
			b |= 1 << h % 2;
	}
	if (b == 3)
		return;
	cc[i][j] = 1, kk[i + j]--;
	for (h = 0; h < 4; h++) {
		i_ = i + di[h], j_ = j + dj[h];
		if (i_ >= 0 && i_ < n && j_ >= 0 && j_ < m && cc[i_][j_] == 0)
			dfs(i_, j_);
	}
}

int main() {
	int q, h, i, j, i_, j_;

	scanf("%d%d", &n, &m);
	for (i = 0; i < n; i++)
		for (j = 0; j < m; j++)
			scanf("%d", &cc[i][j]);
	for (i = 0; i < n; i++)
		for (j = 0; j < m; j++)
			if (cc[i][j] == 0)
				kk[i + j]++;
	for (i = 0; i < n; i++)
		for (j = 0; j < m; j++)
			if (cc[i][j] == 0)
				dfs(i, j);
	scanf("%d", &q);
	while (q--) {
		scanf("%d%d", &i, &j), i--, j--;
		if (cc[i][j]) {
			printf("1\n");
			continue;
		}
		if (kk[i + j] == 1)
			printf("0\n");
		else {
			printf("1\n");
			cc[i][j] = 1, kk[i + j]--;
			for (h = 0; h < 4; h++) {
				i_ = i + di[h], j_ = j + dj[h];
				if (i_ >= 0 && i_ < n && j_ >= 0 && j_ < m && cc[i_][j_] == 0)
					dfs(i_, j_);
			}
		}
	}
	return 0;
}

Compilation message (stderr)

furniture.c: In function 'dfs':
furniture.c:14:13: warning: suggest parentheses around '&&' within '||' [-Wparentheses]
   14 |  if (i == 0 && j == 0 || i == n - 1 && j == m - 1)
      |      ~~~~~~~^~~~~~~~~
furniture.c: In function 'main':
furniture.c:35:2: warning: ignoring return value of 'scanf' declared with attribute 'warn_unused_result' [-Wunused-result]
   35 |  scanf("%d%d", &n, &m);
      |  ^~~~~~~~~~~~~~~~~~~~~
furniture.c:38:4: warning: ignoring return value of 'scanf' declared with attribute 'warn_unused_result' [-Wunused-result]
   38 |    scanf("%d", &cc[i][j]);
      |    ^~~~~~~~~~~~~~~~~~~~~~
furniture.c:47:2: warning: ignoring return value of 'scanf' declared with attribute 'warn_unused_result' [-Wunused-result]
   47 |  scanf("%d", &q);
      |  ^~~~~~~~~~~~~~~
furniture.c:49:3: warning: ignoring return value of 'scanf' declared with attribute 'warn_unused_result' [-Wunused-result]
   49 |   scanf("%d%d", &i, &j), i--, j--;
      |   ^~~~~~~~~~~~~~~~~~~~~

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