Subsets II

Problem

Given a list of numbers that may has duplicate numbers, return all possible subsets

Example

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

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

Note

• Each element in a subset must be in non-descending order.
• The ordering between two subsets is free.
• The solution set must not contain duplicate subsets.

Challenge

Can you do it in both recursively and iteratively?

Key Point

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