Given a collection of numbers, nums, that might contain duplicates, return all possible unique permutations in any order.
Example 1:
Input: 1 1 2 Output: 1 1 2 1 2 1 2 1 1
Example 2:
Input: 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
Input format: Space-separated integers.
Output format: Each unique permutation on its own line, in lexicographic order.