The question never states if the array is sorted in increasing or decreasing order. But then one of the test cases has an array in decreasing order. This breaks the logic of finding the closest value through binary search since the solution they provided, binary search algo assumes the array is increasing order.

Custom Testcase :

[12,10, 9,7,6,3,2,1] X= 4 ,K = 2

Expected Result:

[2,3] or [3,6]

Actual Result:

[9,10]