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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 k=sc.nextInt();
  16. 		int a[]=new int[n];
  17. 		for(int i=0;i<n;i++)
  18. 		a[i]=sc.nextInt();
  19.  
  20. 		Map<Integer,Integer> hash=new HashMap<>();
  21.  
  22. 		int count=0;
  23. 		for(int ele:a)
  24. 		{
  25. 			int cpl1=k-ele;
  26. 			int cpl2=k+ele;
  27.  
  28. 			if(hash.containsKey(cpl1 ))
  29. 			count+=hash.get(cpl1);
  30. 			if(hash.containsKey(cpl2))
  31. 			count+=hash.get(cpl2);
  32.  
  33. 			hash.put(ele,hash.getOrDefault(ele,0)+1);
  34. 		}
  35.  
  36. 		System.out.println(count);
  37.  
  38. 	}
  39. }
Success #stdin #stdout 0.13s 56604KB
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https://ideone.com/BfgYTE
language:
Java (HotSpot 12)
created:
7 hours ago
visibility:
public

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