[leetcode][108]. Convert Sorted Array to Binary Search Tree

Given an array where elements are sorted in ascending order, convert it to a height balanced BST.

# Definition for a binary tree node.# class TreeNode(object):#     def __init__(self, x):#         self.val = x#         self.left = None#         self.right = Noneclass Solution(object):    def sortedArrayToBST(self, nums):        """        :type nums: List[int]        :rtype: TreeNode        """        if len(nums) == 0:            return None        if len(nums) == 1:            return TreeNode(nums[0])                    def insert(nums):            if len(nums) == 1:                return TreeNode(nums[0])            if len(nums) == 0:                return None            left = 0            right = len(nums)            mid = (left+right)//2            node = TreeNode(nums[mid])            node.left = insert(nums[:mid])            node.right = insert(nums[mid+1:])            return node        return insert(nums)