All problems

Permutations

Medium · backtracking

Given a list nums of distinct integers, return every possible permutation: every way to arrange all the numbers in a row, each number used exactly once.

The permutations may be returned in any order. Each permutation is a full-length list, and the result must contain no duplicates.

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]]

Three numbers give 3! = 6 arrangements. Their order in the answer does not matter.

Example 2

Input: nums = [0, 1]

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

Here the order inside each list matters: [0, 1] and [1, 0] are different permutations.

Example 3

Input: nums = [7]

Output: [[7]]

Constraints

• 1 <= len(nums) <= 6
• -10 <= nums[i] <= 10
• All the numbers in nums are distinct.