#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; }

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--;
      |   ^~~~~~~~~~~~~~~~~~~~~