Given an integer array input_array containing unique elements, return a list of all possible subsets (the power set) of input_array. The output must not contain duplicate subsets. The order of subsets in the output can be arbitrary.
Example 1
Input: [4, 5]
Output: [[], [4], [5], [4, 5]]
Explanation: All possible subsets of [4, 5] are listed.
Example 2
Input: [-1, 2, 3]
Output: [[], [-1], [2], [-1, 2], [3], [-1, 3], [2, 3], [-1, 2, 3]]
Explanation: All possible subsets of [-1, 2, 3] are listed.
Constraints
Case 1
Input: [7]
Expected: [[], [7]]
Case 2
Input: [2, 0]
Expected: [[], [2], [0], [2, 0]]
Case 3
Input: [-2, 1, 4]
Expected: [[], [-2], [1], [-2, 1], [4], [-2, 4], [1, 4], [-2, 1, 4]]