46 全排列

给定一个 没有重复 数字的序列，返回其所有可能的全排列。

示例:

输入: [1,2,3]
输出:
[
  [1,2,3],
  [1,3,2],
  [2,1,3],
  [2,3,1],
  [3,1,2],
  [3,2,1]
]

解法

class Solution:
    def permute(self, nums: List[int]) -> List[List[int]]:
        length = len(nums)
        res = [None for _ in range(length)]
        total = []

        def test(nums,index,res):
            if index == length:
                total.append(res.copy())
                return

            for i in range(len(nums)):
                res[index] = nums[i]
                test(nums[:i]+nums[i+1:],index+1,res)

        test(nums,0,res)
        return total