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  1. /* package whatever; // don't place package name! */
  2.  
  3. import java.util.*;
  4. import java.lang.*;
  5. import java.io.*;
  6.  
  7. /* Name of the class has to be "Main" only if the class is public. */
  8. class Ideone
  9. {
  10. 	public static void main (String[] args) throws java.lang.Exception
  11. 	{
  12. 		// your code goes here
  13. 		Scanner sc=new Scanner(System.in);
  14. 		int n=sc.nextInt();
  15. 		int a[]=new int[n+1];
  16. 		for(int i=1;i<=n;i++) a[i]=sc.nextInt();
  17. 		Map<Integer,Integer>mp=new HashMap<>();
  18. 		int i=1;
  19. 		int count=0;
  20. 		while(i<=n){
  21. 			int RHS=a[a[a[i]]];
  22. 			count=count+mp.getOrDefault(RHS,0);
  23. 			mp.put(RHS,mp.getOrDefault(RHS,0)+1);
  24. 			i++;
  25. 		}
  26. 		System.out.println(count);
  27. 	}
  28. }
Success #stdin #stdout 0.13s 56620KB
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4
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6
https://ideone.com/xm9V5k
language:
Java (HotSpot 12)
created:
9 hours ago
visibility:
public

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