46. 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]]:
        if len(nums) == 0:
            return [[]]
        res = []
        permutations = self.permute(nums[1:])
        print(permutations)
        for p in permutations:
            for i in range(len(p)+ 1):
                p_copy = p.copy()
                p_copy.insert(i, nums[0])
                res.append(p_copy)
        return res