Given an array arr[] of length n. Find all possible unique permutations of the array.
Example 1:
Input:
n = 3
arr[] = {1, 2, 1}
Output:
1 1 2
1 2 1
2 1 1
Explanation:
These are the only possible unique permutations
for the given array.
Example 2:
Input:
n = 2
arr[] = {4, 5}
Output:
4 5
5 4
Your Task:
You don't need to read input or print anything. You only need to complete the function uniquePerms() that takes an integer n, and an array arr of size n as input and returns a sorted list of lists containing all unique permutations of the array.
Expected Time Complexity: O(nn!)
Expected Auxilliary Space: O(nn!)

Constraints:
1 ≤ n ≤ 9
1 ≤ arr_{i} ≤ 10

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