Submission #587258

#	Time	Username	Problem	Language	Result	Execution time	Memory
587258		rainboy	Naboj (COCI22_naboj)	C11	110 / 110	386 ms	25088 KiB

naboj

#include <stdio.h>
#include <stdlib.h>

#define N	200000
#define M	500000

int ij[M];
int *eh[N], eo[N];

void append(int i, int h) {
	int o = eo[i]++;

	if (o >= 2 && (o & o - 1) == 0)
		eh[i] = (int *) realloc(eh[i], o * 2 * sizeof *eh[i]);
	eh[i][o] = h;
}

char visited[N]; int dd[N][2], ii[N], cc[N], cnt;

void dfs(int i) {
	int o;

	if (visited[i] || dd[i][0] > 0 && dd[i][1] > 0)
		return;
	visited[i] = 1;
	ii[cnt] = i, cc[cnt] = dd[i][0] == 0 ? 0 : 1, cnt++;
	for (o = eo[i]; o--; ) {
		int h = eh[i][o], j = i ^ ij[h >> 1];

		dd[j][h & 1 ^ 1]--, dfs(j);
	}
}

int main() {
	int n, m, h, i, j;

	scanf("%d%d", &n, &m);
	for (i = 0; i < n; i++)
		eh[i] = (int *) malloc(2 * sizeof *eh[i]);
	for (h = 0; h < m; h++) {
		scanf("%d%d", &i, &j), i--, j--;
		ij[h] = i ^ j;
		append(i, h << 1 | 0), dd[i][0]++;
		append(j, h << 1 | 1), dd[j][1]++;
	}
	for (i = 0; i < n; i++)
		dfs(i);
	for (i = 0; i < n; i++)
		if (!visited[i]) {
			printf("-1\n");
			return 0;
		}
	printf("%d\n", cnt);
	while (cnt--)
		printf("%d %d\n", ii[cnt] + 1, cc[cnt]);
	return 0;
}

Compilation message (stderr)

naboj.c: In function 'append':
naboj.c:13:23: warning: suggest parentheses around '-' in operand of '&' [-Wparentheses]
   13 |  if (o >= 2 && (o & o - 1) == 0)
      |                     ~~^~~
naboj.c: In function 'dfs':
naboj.c:23:33: warning: suggest parentheses around '&&' within '||' [-Wparentheses]
   23 |  if (visited[i] || dd[i][0] > 0 && dd[i][1] > 0)
      |                    ~~~~~~~~~~~~~^~~~~~~~~~~~~~~
naboj.c:30:11: warning: suggest parentheses around arithmetic in operand of '^' [-Wparentheses]
   30 |   dd[j][h & 1 ^ 1]--, dfs(j);
      |         ~~^~~
naboj.c: In function 'main':
naboj.c:37:2: warning: ignoring return value of 'scanf' declared with attribute 'warn_unused_result' [-Wunused-result]
   37 |  scanf("%d%d", &n, &m);
      |  ^~~~~~~~~~~~~~~~~~~~~
naboj.c:41:3: warning: ignoring return value of 'scanf' declared with attribute 'warn_unused_result' [-Wunused-result]
   41 |   scanf("%d%d", &i, &j), i--, j--;
      |   ^~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 15 / 15
• Subtask 2: 25 / 25
• Subtask 3: 70 / 70