Leetcode: Convert Sorted Array to Binary Search Tree

bst_from_array.py

class bst_node:
    def __init__(self, val, left=None, right=None):
        self.val = val
        self.left = left
        self.right = right

# assumes arr is sorted
def bst_from_array(arr):
    if len(arr) == 0:
        return None

    mid = len(arr) // 2
    root = bst_node(arr[mid])

    root.right = bst_from_array(arr[mid + 1 :])
    root.left = bst_from_array(arr[:mid])

    return root