Submission #2091053

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Source Code Expand

#include <bits/stdc++.h>
using namespace std;
#define ll long long int
#define rep(i,n) for( int i = 0; i < n; i++ )
#define dump(x)  cerr << #x << " = " << (x) << endl;
#define INF 2000000000
#define mod 1000000007
#define INF2 1000000000000000000


int main(void)
{
    cin.tie(0);
    ios::sync_with_stdio(false);
    int N; cin >> N;
    int a[N]; 
    rep(i, N)cin >> a[i];
    int ans = 0;
    rep(i, N) {
        if(a[a[i]-1] == i+1) ans++;
    }
    cout << ans/2 << endl;


    return 0;
}

Submission Info

Judge Result