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]] BackTracking 回溯法： 修改当前值 递归current node 还原当前值 def permute(self, nums):
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:type nums: List[int]
:rtype: List[List[int]]
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def backTrack(nums, level):
if level == len(nums)-1:
self.ans.append(list(nums))
return