Maximum XOR


There is an array of positive integers given. You have to find an integer denoting the maximum XOR subset value in the given array.

Write a function solve that have the following parameter(s):
1.) arr = an array of integer

Example
Input:
arr = [1, 2, 3]
Output:
3

Explanation
The subset {1, 2} has maximum subset XOR value.

Constraints
• Number of elements in an array will be greater than or equal to 1 and less than or equal to 10.
• Every element in an array will be greater than or equal to 1 and less than or equal to 10000.