Given an integer array input_array containing unique elements, return a list of all possible subsets (the power set) of input_array. Each subset should be represented as a list, and the solution should not contain duplicate subsets. The order of subsets in the output does not matter.
Example 1
Input: [4, 5]
Output: [[], [4], [5], [4, 5]]
Explanation: All possible subsets of [4, 5] are listed.
Example 2
Input: [-2, 0, 2]
Output: [[], [-2], [0], [-2, 0], [2], [-2, 2], [0, 2], [-2, 0, 2]]
Explanation: All possible subsets of [-2, 0, 2] are listed.
Constraints
Case 1
Input: [7]
Expected: [[], [7]]
Case 2
Input: [-1, 1]
Expected: [[], [-1], [1], [-1, 1]]
Case 3
Input: [3, 6, 9]
Expected: [[], [3], [6], [3, 6], [9], [3, 9], [6, 9], [3, 6, 9]]