Submission #381149

#	Time	Username	Problem	Language	Result	Execution time	Memory
381149		rainboy	Duathlon (APIO18_duathlon)	C11	8 / 100	46 ms	2788 KiB

count_triplets

#include <stdio.h>
#include <string.h>

#define N	100000
#define M	200000

int ds[N], mm[N], nn[N];

int find(int i) {
	return ds[i] < 0 ? i : (ds[i] = find(ds[i]));
}

void join(int i, int j) {
	i = find(i);
	j = find(j);
	if (i == j) {
		mm[i]++;
		return;
	}
	if (ds[i] > ds[j])
		ds[i] = j, mm[j] += mm[i] + 1, nn[j] += nn[i];
	else {
		if (ds[i] == ds[j])
			ds[i]--;
		ds[j] = i, mm[i] += mm[j] + 1, nn[i] += nn[j];
	}
}

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

	scanf("%d%d", &n, &m);
	memset(ds, -1, n * sizeof *ds);
	for (i = 0; i < n; i++)
		nn[i] = 1;
	for (h = 0; h < m; h++) {
		scanf("%d%d", &i, &j), i--, j--;
		join(i, j);
	}
	ans = 0;
	for (i = 0; i < n; i++)
		if (ds[i] < 0)
			ans += nn[i] == mm[i] ?  (long long) nn[i] * (nn[i] - 1) * (nn[i] - 2) : (long long) nn[i] * (nn[i] - 1) * (nn[i] - 2) / 3;
	printf("%lld\n", ans);
	return 0;
}

Compilation message (stderr)

count_triplets.c: In function 'main':
count_triplets.c:33:2: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
   33 |  scanf("%d%d", &n, &m);
      |  ^~~~~~~~~~~~~~~~~~~~~
count_triplets.c:38:3: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
   38 |   scanf("%d%d", &i, &j), i--, j--;
      |   ^~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 0 / 5
• Subtask 2: 0 / 11
• Subtask 3: 8 / 8
• Subtask 4: 0 / 10
• Subtask 5: 0 / 13
• Subtask 6: 0 / 15
• Subtask 7: 0 / 20
• Subtask 8: 0 / 8
• Subtask 9: 0 / 10