Given an array of integers, where all elements but one occur twice, find the unique element.
arr = [4, 9, 95, 93, 57, 4, 57, 93, 9]
The unique element is 95.
lonelyinteger has the following parameter(s):
- int a[n]: an array of integers
- int: the element that occurs only once
- 1 <= n < 100
- It is guaranteed that n is an odd number and that there is one unique element.
- 0 <= a[i] <= 100, where 0 <= i < n.