Given an unsorted array of n elements, find if the
element k is present in the array or not.
Complete the findNumber function in the editor below.
It has 2 parameters:
1. An array of integers, arr, denoting the elements in the
array.
2. An integer, k, denoting the element to be searched in
the array.
The function must return a string "YES" or
"NO" denoting if the element is present in the array or
not.