Problem: Wave Array
Given an array of integers, sort the array into a wave like array and return it, In other words, arrange the elements into a sequence such that
a1 >= a2 <= a3 >= a4 <= a5.....
Given [1, 2, 3, 4] One possible answer : [2, 1, 4, 3] Another possible answer : [4, 1, 3, 2]
NOTE : If there are multiple answers possible, return the one that's lexicographically smallest. So, in the example case, you will return [2, 1, 4, 3]