"""
46. Permutations
Difficulty: Medium
https://leetcode.com/problems/permutations/

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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.
"""


class Solution:
    def permute(self, nums: list[int]) -> list[list[int]]:
        result, path = [], []
        used = [False] * len(nums)

        def backtrack():
            if len(path) == len(nums):
                result.append(path[:])
                return
            for i in range(len(nums)):
                if used[i]:
                    continue
                used[i] = True
                path.append(nums[i])
                backtrack()
                path.pop()
                used[i] = False

        backtrack()
        return result