Freshman's Database

#include <iostream>
#include <cstring>
using namespace std;
static const int N =1E6+1;
int n, val, ink[N]; 
int visited[N];
int main() {
    cin >> n;
    for (int i=0; i<n; i++) {
        int val;
        cin >> val;
        ink[i+1] = val;
    }
    int cnt = 0;
    for (int i=1; i<=n; i++) {
        if (visited[i]) continue;
        int j = i;
        cnt++;
        while (!visited[j]) {
            visited[j] = i;
            j = ink[j];
        }
        if (visited[j] != i) cnt--; 
    }
    cout << cnt << endl;
}

Test 1

Verdict: ACCEPTED

Test 2

Verdict: ACCEPTED

Test 3

Verdict: ACCEPTED

Test 4

Verdict: ACCEPTED

Test 5

Verdict: ACCEPTED

Test 6

Verdict: ACCEPTED

Test 7

Verdict: ACCEPTED

Test 8

Verdict: ACCEPTED

Test 9

Verdict: ACCEPTED

Test 10

Verdict: ACCEPTED