90. Subsets II

Description

Given a collection of integers that might contain duplicates, nums, return all possible subsets (the power set).

Note: The solution set must not contain duplicate subsets.

Example:

Input: [1,2,2]

Output:

[

  [2],

  [1],

  [1,2,2],

  [2,2],

  [1,2],

  []

]