Witch game

input/code.cpp: In function 'int main()':
input/code.cpp:14:16: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d",&n);
                ^
input/code.cpp:16:20: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d",&p[i]);
                    ^

#include <bits/stdc++.h>
using namespace std;
typedef long long lint;
typedef long double llf;

int n, p[100005];
vector<int> gph[100005];

lint nc2(lint x){
	return x * (x-1) / 2;
}

int main(){
	scanf("%d",&n);
	for(int i=1; i<=n; i++){
		scanf("%d",&p[i]);
		gph[i].push_back(p[i]);
		gph[p[i]].push_back(i);
	}
	int ecnt = 0;
	for(int i=1; i<=n; i++){
		sort(gph[i].begin(), gph[i].end());
		gph[i].resize(unique(gph[i].begin(), gph[i].end()) - gph[i].begin());
		ecnt += gph[i].size();
	}
	ecnt /= 2;
	lint ans = 0;
	for(int i=1; i<=n; i++){
		if(p[p[p[i]]] == i) ans--;
		ans += nc2(n - (int)gph[i].size() - 1);
		for(auto &j : gph[i]){
			ans += gph[j].size();
		}
		ans -= ecnt;
	}
	cout << ans/3;
}

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