Submission #891249

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Source Code Expand

#include <iostream>
#include <iomanip>
#include <cmath>
#include <algorithm>
#include <functional>
#include <vector>
#include <map>
#include <set>
#include <tuple>

using namespace std;

#define D(x) x
#define REP(i,a,b) for (int i = (a); i < (b); ++i)

int main() {
    ios_base::sync_with_stdio(false);
    cout << setprecision(12) << fixed;

    int N; cin >> N;
    int x[N];
    REP(i,0,N) {
        cin >> x[i];
        x[i]--;
    }

    int res = 0;
    REP(i,0,N) {
        if (x[i] > i && x[x[i]] == i)
            res++;
    }

    cout << res << endl;

	return 0;
}

Submission Info

Judge Result