Convert sorted array to binary search tree

# Definition for a binary tree node.
# class TreeNode:
#     def __init__(self, val=0, left=None, right=None):
#         self.val = val
#         self.left = left
#         self.right = right
class Solution:
    def buildTree(self, nums, left, right) -> TreeNode:
        if left > right:
            return None
        mid = (left + right) // 2
        root = TreeNode(nums[mid])
        root.left = self.buildTree(nums, left, mid - 1)
        root.right = self.buildTree(nums, mid + 1, right)

        return root

    def sortedArrayToBST(self, nums: List[int]) -> Optional[TreeNode]:
        return self.buildTree(nums, 0, len(nums) - 1)

Convert Sorted Array to Binary Search Tree

Difficulty: Easy


Given an integer array nums where the elements are sorted in ascending order, convert it to a height-balanced binary search tree.

 

Example 1:

Input: nums = [-10,-3,0,5,9]
Output: [0,-3,9,-10,null,5]
Explanation: [0,-10,5,null,-3,null,9] is also accepted:

Example 2:

Input: nums = [1,3]
Output: [3,1]
Explanation: [1,null,3] and [3,1] are both height-balanced BSTs.

 

Constraints:

  • 1 <= nums.length <= 104
  • -104 <= nums[i] <= 104
  • nums is sorted in a strictly increasing order.