Write a Program to find K-complementary pairs in a given array of integers [Java interview]

Write a Program to find K-complementary pairs in a given array of integers

This article will help you to understand “Java Program to find k-Complementary Pairs.”

If Arr is Given Array, then pair (i, j) is K-complementary if K = Arr[i] + Arr[j]; 

Java Program to find k-Complementary Pairs

package com.codenuclear;

		
	

public class KComplementaryPairs {
	
	public static void main(String args[])
	{
		KComplementaryPairs obj = new KComplementaryPairs();
		int[] array = {2,5,7,1,4,2};
		int k = 6;
		System.out.println("\nTotal K Complementary Pairs :- "+obj.findKComplementaryPairs(array, k));
		
	}
	
	public int findKComplementaryPairs(int[] array, int K)
	{
	  int count = 0;
	  int arrLength = array.length;
	  
	  for(int i = 0; i < arrLength; i++) 
	  {
	    for (int j = i; j < arrLength; j++ ) 
	    {
	    	if (array[ i ] + array[ j ] == K ) 
	    	{
 
		        if ( i != j ) 
		        {
		        	System.out.println("K-Complementary Pair :- ("+array[i]+" , "+array[j]+")");
		        	System.out.println("K-Complementary Pair :- ("+array[j]+" , "+array[i]+")");
		    		// Here count incremented by 2 when i!=j, 
		    		// the reason is K = Arr[i] + Arr[j] as well as K = Arr[j] + Arr[i], so we found two pairs (i,j) and (j,i).
		        	count += 2;
		        }
		        
		        else
		        {
		        	System.out.println("K-Complementary Pair :- ("+array[i]+" , "+array[j]+")");
		        	count++;
		        }
	    	}
	    }
	  }
	  
	  return count;
	}

}

Output K-Complementary Pair :- (2 , 4) K-Complementary Pair :- (4 , 2) K-Complementary Pair :- (5 , 1) K-Complementary Pair :- (1 , 5) K-Complementary Pair :- (4 , 2) K-Complementary Pair :- (2 , 4) Total K Complementary Pairs :- 6