Submission #890795

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Source Code Expand

//Daniel Grzegorzewski
#include <bits/stdc++.h>

#define MP make_pair
#define PB push_back
#define ST first
#define ND second

using namespace std;

typedef pair<int, int> PII;
typedef vector<int> VI;
typedef vector<PII> VII;
typedef long long LL;

void init_ios()
{
     ios_base::sync_with_stdio(0);
     cin.tie(0);
}

const int N = (int)1e5 + 10;

int n, a[N], res;
bool vis[N];

int main()
{
    init_ios();
    cin >> n;
    for (int i = 1; i <= n; ++i)
    	cin >> a[i];
    for (int i = 1; i <= n; ++i)
    	if (!vis[i] && a[a[i]] == i) {
    		++res;
    		vis[a[i]] = true;
    	}
    cout<<res<<"\n";
}

Submission Info

Judge Result