Permutations

Given an array nums of distinct integers, return all the possible permutations. You can return the answer in any order.

Example 1:

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

Example 2:

Input: nums = [0,1]
Output: [[0,1],[1,0]]

Example 3:

Input: nums = [1]
Output: [[1]]

Constraints:

• 1 <= nums.length <= 6
• -10 <= nums[i] <= 10
• All the integers of nums are unique.

SOLUTION:

class Solution:
    def permute(self, nums: List[int]) -> List[List[int]]:
        n = len(nums)
        paths = [([num], {num}, 1) for num in nums]
        while paths[0][2] < n:
            curr, currSet, l = paths.pop(0)
            for num in nums:
                if num not in currSet:
                    paths.append((curr + [num], currSet.union({num}), l + 1))
        return [perm[0] for perm in paths]