Subsets

Problem

Given a set of distinct integers, S, return all possible subsets.

Note: Elements in a subset must be in non-descending order.

The solution set must not contain duplicate subsets.

Example

If S = [1,2,3], a solution is:

[
  [3],
  [1],
  [2],
  [1,2,3],
  [1,3],
  [2,3],
  [1,2],
  []
]

Key Point

Elements in a subset must be in non-descending order.