测试用例[-10,-3,0,5,9],前面是我的写法,返回结果是[]

class TreeNode:     def __init__(self, x):         self.val = x         self.left = None         self.right = None  class Solution:     def sortedArrayToBST(self, nums: List[int]) -> TreeNode:                  if not nums:             return None         else:             middle = len(nums)//2             root =TreeNode(nums[middle])             root.left=self.sortedArrayToBST(nums[0:middle])             root.right=self.sortedArrayToBST(nums[middle+1:len(nums)])          return root 

后面是路人的写法,可以 AC

class Solution:     def sortedArrayToBST(self, nums):         """         :type nums: List[int]         :rtype: TreeNode         """         if not nums:             return None         else:             mid=len(nums)//2             tn=TreeNode(nums[mid])             nums1=nums[0:mid]             nums2=nums[mid+1:len(nums)]             tn.left=self.sortedArrayToBST(nums1)             tn.right=self.sortedArrayToBST(nums2)         return tn 

感觉很奇怪啊,不知道为什么