LeetCode_Convert Sorted Array to Binary Search Tree

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Convert Sorted Array to Binary Search Tree

Given an array where elements are sorted in ascending order, convert it to a height balanced BST. For this problem, a height-balanced binary tree is defined as a binary tree in which the depth of the two subtrees of every node never differ by more than 1.
（将有序数组转换为平衡二叉树）

Example:



1. 递归

根据平衡二叉树的定义：height差不大于1。因此从中间开始建立为根节点，左边的有序数组构建左子树，右边的有序数组构建右子树。具体实现过程如下：

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# Definition for a binary tree node.
# 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
        
        n = len(nums)
        root = TreeNode(nums[n//2])
        root.left = self.sortedArrayToBST(nums[:n//2])
        root.right = self.sortedArrayToBST(nums[n//2+1:])
        
        return root