[Solved] Given a collection of numbers, nums, that might contain duplicates, return all possible unique permutations in any order.

Question

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

Python Solution

class Solution:
    def permuteUnique(self, nums):
        if len(nums)==0:
            return []
        result = []
        nums.sort()
        return self.recursive(nums,0,result)
    
        
    def recursive(self, nums, start, result):
        myset = set()
        if start>=len(nums)-1:
            #print(start,nums)
            result.append(nums[:])
            return result
        
        for i in range(start,len(nums)):
            #print(start,i)
            if nums[i] not in myset:
                myset.add(nums[i])
                nums[start], nums[i] = nums[i], nums[start]
                self.recursive(nums,start+1,result)
                nums[start], nums[i] = nums[i], nums[start]
            
        return result
Abhishek Sharma
Abhishek Sharma

Started my Data Science journey in my 2nd year of college and since then continuously into it because of the magical powers of ML and continuously doing projects in almost every domain of AI like ML, DL, CV, NLP.

Articles: 520

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