Submission #891051

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Source Code Expand

#include <bits/stdc++.h>
using namespace std;

#define debug(x) cout << #x << " = " << x << endl

const int INF = 1<<29;
typedef long long ll;
typedef pair<int,int> P;


int main(){
   int n;
   cin >> n;
   int ans = 0;
   int a[n];
   for(int i=0; i<n; i++){
	  cin >> a[i];
	  a[i]--;
   }
   
   for(int i=0; i<n; i++){
	  if(a[i] == -1) continue;
	  if(a[a[i]] == i){
		 ans++;
		 a[i] = a[a[i]] = -1;
	  } 
   }
   
   cout << ans << endl;
   return 0;
}

Submission Info

Judge Result