Write a method isAllUnique which takes an integer array as an argument and returns true if every element in the array is distinct (not equal to) every other element. For example, the array {3, -1, 2} is all unique and the method would return true with argument but {3, -1, 3} is not because the first and third elements are equal so the method would return false. If an array has one element, all the elements must be unique.