Witch game

input/code.cpp: In function 'int main()':
input/code.cpp:12:17: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d", &n);
                 ^
input/code.cpp:15:21: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d", &a[i]);
                     ^

#include <bits/stdc++.h>
using namespace std;

// why am I so weak

int n;
int a[100055];
int cnt[100055];
vector<int> g[100055];

int main() {
	scanf("%d", &n);

	for (int i = 0; i < n; i++) {
		scanf("%d", &a[i]);
		a[i]--;

		g[a[i]].push_back(i);
	}

	long long res = 1ll * n * (n - 1) * (n - 2) / 6ll;

	for (int i = 0; i < n; i++) {
		if (a[a[i]] == i) {
			if (i > a[i]) continue;

			res -= 1ll * (n - 2 - (int)(g[a[i]].size() + g[i].size() - 2));
			continue;
		}

		if (a[a[a[i]]] == i) {
			res -= 1ll * (n - 2 - (int)g[i].size());
		} else res -= 1ll * (n - 2 - (int)g[i].size() - 1);

		res += 1ll * cnt[a[i]];

		cnt[a[i]]++;
	}

	for (int i = 0; i < n; i++) {
		if (a[a[i]] == i) continue;

		if (a[a[a[i]]] == i) {
			if (min(min(i, a[i]), a[a[i]]) == i) {
				res--;
			} 

			continue;
		}

		res--;
	}

	printf("%lld\n", max(0ll, res));

	return 0;
}

Test 1

Group: 1

Verdict: ACCEPTED

Test 2

Group: 1

Verdict: ACCEPTED

Test 3

Group: 1

Verdict: ACCEPTED

Test 4

Group: 1

Verdict: ACCEPTED

Test 5

Group: 1

Verdict: ACCEPTED

Test 6

Group: 2

Verdict: ACCEPTED

Test 7

Group: 2

Verdict: ACCEPTED

Test 8

Group: 2

Verdict: ACCEPTED

Test 9

Group: 2

Verdict: ACCEPTED

Test 10

Group: 2

Verdict: ACCEPTED

Test 11

Group: 3

Verdict: ACCEPTED

Test 12

Group: 3

Verdict: ACCEPTED

Test 13

Group: 3

Verdict: ACCEPTED

Test 14

Group: 3

Verdict: ACCEPTED

Test 15

Group: 3

Verdict: ACCEPTED