Solving Permutations II in Javascript. Please try yourself first to solve the problem and submit your implementation to LeetCode before looking into solution.

Problem Description

Given a collection of numbers that might contain duplicates, return all possible unique permutations.

Example:

Input: [1,1,2]

Output:
[
  [1,1,2],
  [1,2,1],
  [2,1,1]
]

See the full details of the problem Permutations II at LeetCode

Originally posted at: @github.com/ignacio-chiazzo/Algorithms-Leetcode-Javascript