Generate all permutations of an array

## Problem Given an array `nums` of **distinct** integers, return **all possible permutations** of the array. A permutation is an ordering of all elements in the array, and each element must appear **exactly once** in each permutation. ## Input - `nums`: an array of integers with no duplicates. ## Output - A list of permutations, where each permutation is a list/array of integers. - You may return the permutations in **any order**. ## Constraints - `1 <= nums.length <= 10` - `-10 <= nums[i] <= 10` - All values in `nums` are unique. ## Example **Input:** `nums = [1,2,3]` **Output (one valid ordering):** ``` [ [1,2,3], [1,3,2], [2,1,3], [2,3,1], [3,1,2], [3,2,1] ] ``` ## Notes - Aim for a solution using DFS/backtracking. - Consider how to track which elements have been used in the current partial permutation.