Challenge: Find Two Pairs in an Array such that a+b = c+d

Problem Statement

In this problem, you have to implement the findPair() function to find two pairs or 4 elements (a,b,c,d) in an array, such that,

$$a+b = c+d$$

You only have to find first two pairs in the array which satisfies the above condition. An illustration is also provided for your understanding.

$$$$

Function Prototype:

String findPair(int[] arr);

Here, arr is an Integer array.

Output:

It returns a String containing two pairs, (a,b) and (c,d), which satisfies a+b = c+d.

Sample Input

arr = {3, 4, 7, 1, 12, 9}

Sample Output

"{4,12}{7,9}"

Explanation

4,12,7 and 9 follow the above condition, as 4+12 = 7+9. There are so many other possible pairs in the sample input that satisfy the above condition, but for this problem, we only have to find one of them.