Find All Permutations

Return all possible permutations of a given array of unique integers. They can be returned in any order.

Example:

Input: nums = [4, 5, 6]
Output: [[4, 5, 6], [4, 6, 5], [5, 4, 6], [5, 6, 4], [6, 4, 5], [6, 5, 4]]