Example 1: What is the output for input nums = [1,2,3]?

Output: [[1,2,3],[1,3,2],[2,1,3],[2,3,1],[3,1,2],[3,2,1]]. All 6 permutations of [1,2,3] are listed.

Example 2: What is the output for input nums = [0,1]?

Output: [[0,1],[1,0]]. There are 2 permutations of a 2-element array.

Example 3: What is the output for input nums = [1]?

Output: [[1]]. A single element has exactly one permutation.

All problems

MediumBacktracking

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]]
Explanation: There are 3! = 6 permutations of [1,2,3].

Example 2:

Input: nums = [0,1]
Output: [[0,1],[1,0]]
Explanation: There are 2 permutations of [0,1].

Example 3:

Input: nums = [1]
Output: [[1]]
Explanation: A single element has only one permutation.

Examples

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]]

Explanation: All 6 permutations of [1,2,3] are listed.

Example 2

Input: nums = [0,1]

Output: [[0,1],[1,0]]

Explanation: There are 2 permutations of a 2-element array.

Example 3

Input: nums = [1]

Output: [[1]]

Explanation: A single element has exactly one permutation.

Constraints

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

Optimal Complexity

Time

O(n! * n)

Space

O(n!)

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