문제 Given an array nums of distinct integers, return all the possible permutations. You can return the answer in any order. 예시 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]] 제약 조건 Constraints: 1