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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.  
  11. 	static int find(int b[], int k )
  12. 	{
  13. 		int n=b.length;
  14. 		Map<Integer,Integer> m=new HashMap<>();
  15. 		Map<Integer,Integer> used=new HashMap<>();
  16.  
  17. 		for(int ele:b)
  18. 		m.put(ele,m.getOrDefault(ele,0)+1);
  19.  
  20. 		int ans=0;
  21. 		for(int ele:b)
  22. 		{
  23. 			int cpl=k-ele;
  24. 			if(m.containsKey(cpl))
  25. 			{
  26. 				if(!used.containsKey(ele) && !used.containsKey(cpl))
  27. 				{
  28. 					if(cpl==ele)
  29. 					ans+=m.get(cpl)/2;
  30. 					else
  31. 					ans+=Math.min(m.get(ele), m.get(cpl));
  32.  
  33. 					used.put(ele,1);
  34. 					used.put(cpl,1);
  35. 				}
  36. 			}
  37. 		}
  38. 		return ans;
  39. 	}
  40. 	public static void main (String[] args) throws java.lang.Exception
  41. 	{
  42. 		// your code goes here
  43. 		Scanner sc=new Scanner(System.in);
  44. 		int n=sc.nextInt();
  45. 		int b[]=new int[n];
  46. 		for(int i=0;i<n;i++)
  47. 		b[i]=sc.nextInt();
  48.  
  49. 		int temp=0;
  50. 		for(int i=0;i<n;i++)
  51. 		{
  52. 			for(int j=i+1;j<n;j++)
  53. 			{
  54. 				int k=b[i]+b[j];
  55. 				temp=Math.max(temp,find(b,k));
  56. 			}
  57. 		}
  58. 		System.out.println(temp);
  59. 	}
  60. }
Success #stdin #stdout 0.11s 54432KB
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https://ideone.com/9FlDUj
language:
Java (HotSpot 12)
created:
1 day ago
visibility:
public

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