Given a collection of numbers, `nums`

, that might contain duplicates, return *all possible unique permutations **in any order**.*

**Example 1:**

**Input:** nums = [1,1,2]

**Output:**

[[1,1,2],

[1,2,1],

[2,1,1]]

**Example 2:**

**Input:** nums = [1,2,3]

**Output:** [[1,2,3],[1,3,2],[2,1,3],[2,3,1],[3,1,2],[3,2,1]]

**Constraints:**

`1 <= nums.length <= 8`

`-10 <= nums[i] <= 10`

# Solution :

`public class Solution…`