Submission #503306

#	Time	Username	Problem	Language	Result	Execution time	Memory
503306		rainboy	Cijanobakterije (COCI21_cijanobakterije)	C11	70 / 70	55 ms	12536 KiB

Main

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

#define N	100000

int max(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;
}

char visited[N]; int d1;

int dfs(int p, int i) {
	int o, d_;

	visited[i] = 1;
	d_ = 0;
	for (o = eo[i]; o--; ) {
		int j = ej[i][o];

		if (j != p) {
			int d = dfs(i, j);

			d1 = max(d1, d_ + 1 + d), d_ = max(d_, d);
		}
	}
	return d_ + 1;
}

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

	scanf("%d%d", &n, &m);
	for (i = 0; i < n; i++)
		ej[i] = (int *) malloc(2 * sizeof *ej[i]);
	while (m--) {
		scanf("%d%d", &i, &j), i--, j--;
		append(i, j), append(j, i);
	}
	ans = 0;
	for (i = 0; i < n; i++)
		if (!visited[i]) {
			d1 = 1, dfs(-1, i);
			ans += d1;
		}
	printf("%d\n", ans);
	return 0;
}

Compilation message (stderr)

Main.c: In function 'append':
Main.c:13:23: warning: suggest parentheses around '-' in operand of '&' [-Wparentheses]
   13 |  if (o >= 2 && (o & o - 1) == 0)
      |                     ~~^~~
Main.c: In function 'main':
Main.c:40:2: warning: ignoring return value of 'scanf' declared with attribute 'warn_unused_result' [-Wunused-result]
   40 |  scanf("%d%d", &n, &m);
      |  ^~~~~~~~~~~~~~~~~~~~~
Main.c:44:3: warning: ignoring return value of 'scanf' declared with attribute 'warn_unused_result' [-Wunused-result]
   44 |   scanf("%d%d", &i, &j), i--, j--;
      |   ^~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 15 / 15
• Subtask 2: 6 / 6
• Subtask 3: 6 / 6
• Subtask 4: 15 / 15
• Subtask 5: 28 / 28