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  1. #include <iostream>
  2. using namespace std;
  3. #include <bits/stdc++.h>
  4. int main() {
  5. 	// your code goes here
  6. 	int n;
  7. 	cin>>n;
  8. 	int A[n+1]={0};
  9. 	for(int i=1;i<=n;i++)
  10. 	 {
  11. 	 	cin>>A[i];
  12. 	 }
  13.  
  14. 	 unordered_map<int,int>map;
  15. 	 int count=0;
  16. 	 for(int i=1;i<=n;i++)
  17. 	  {
  18. 	  	if(map.find(A[A[A[i]]])!=map.end())
  19. 	  	 {
  20. 	  	 	count+=map[A[A[A[i]]]];
  21. 	  	 }
  22.  
  23. 	     map[A[A[A[i]]]]++;
  24. 	  }
  25.  
  26. 	 cout<<count;
  27. 	return 0;
  28. }
Success #stdin #stdout 0.01s 5288KB
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https://ideone.com/wcAkld
language:
C++ (gcc 8.3)
created:
39 days ago
visibility:
public

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