Submission #1590380

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Source Code Expand

#include<iostream>
#include<string>
#include<string.h>
#include<algorithm>
#include<stdio.h>
#include<cmath>
#include<vector>

#define FOR(i, a, b) for(int i=(a);i<=(b);i++)
#define RFOR(i, a, b) for(int i=(a);i>=(b);i--)
using namespace std;

int main(void) {
	int n;
	int count = 0;
	int* a;
	int* flag;
	cin >> n;
	a = new int[n + 1];
	flag = new int[n + 1]();
	FOR(i, 1, n) {
		cin >> a[i];
	}
	FOR(i, 1, n) {
		if (flag[i] == 1) {
			continue;
		}
		if (a[a[i]] == i) {
			count++;
			flag[a[i]] = 1;
		}
	}
	cout << count << endl;
	return 0;
}

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