78\. Subsets

Medium

Given an integer array `nums` of **unique** elements, return _all possible subsets (the power set)_.

The solution set **must not** contain duplicate subsets. Return the solution in **any order**.

**Example 1:**

**Input:** nums = [1,2,3]

**Output:** [[],[1],[2],[1,2],[3],[1,3],[2,3],[1,2,3]] 

**Example 2:**

**Input:** nums = [0]

**Output:** [[],[0]] 

**Constraints:**

*   `1 <= nums.length <= 10`
*   `-10 <= nums[i] <= 10`
*   All the numbers of `nums` are **unique**.