Submission #949047

#	Time	Username	Problem	Language	Result	Execution time	Memory
949047		rainboy	작은 사이클들 (YDX13_smallcycles)	C11	1 / 1	41 ms	13904 KiB

E

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

#define N	100000
#define M	100000

int min(int a, int b) { return a < b ? a : b; }

int *ej[N], eo[N];

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

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

int ta[N], tb[N], sz[N], ans;

void dfs(int p, int i) {
	static int t;
	int o;

	ta[i] = tb[i] = ++t;
	sz[i] = 1;
	for (o = eo[i]; o--; ) {
		int j = ej[i][o];

		if (j != p) {
			if (!ta[j]) {
				dfs(i, j);
				if (tb[j] == ta[j])
					sz[i] += sz[j];
				else
					ans += (sz[j] - 1) / 2, tb[i] = min(tb[i], tb[j]);
			} else
				tb[i] = min(tb[i], ta[j]);
		}
	}
}

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

	scanf("%d%d", &n, &m);
	for (i = 0; i < n; i++)
		ej[i] = (int *) malloc(2 * sizeof *ej[i]);
	for (h = 0; h < m; h++) {
		scanf("%d%d", &i, &j), i--, j--;
		append(i, j), append(j, i);
	}
	dfs(-1, 0);
	ans += (sz[0] - 1) / 2;
	printf("%d\n", ans);
	return 0;
}

Compilation message (stderr)

E.c: In function 'append':
E.c:14:23: warning: suggest parentheses around '-' in operand of '&' [-Wparentheses]
   14 |  if (o >= 2 && (o & o - 1) == 0)
      |                     ~~^~~
E.c: In function 'main':
E.c:46:2: warning: ignoring return value of 'scanf' declared with attribute 'warn_unused_result' [-Wunused-result]
   46 |  scanf("%d%d", &n, &m);
      |  ^~~~~~~~~~~~~~~~~~~~~
E.c:50:3: warning: ignoring return value of 'scanf' declared with attribute 'warn_unused_result' [-Wunused-result]
   50 |   scanf("%d%d", &i, &j), i--, j--;
      |   ^~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 1 / 1