-
Notifications
You must be signed in to change notification settings - Fork 0
/
sorted_array_to_BST.py
39 lines (31 loc) · 1.07 KB
/
sorted_array_to_BST.py
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
from typing import Optional
# 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:
"""
Task:
Given an integer array nums where the elements are sorted in ascending order,
convert it to a height-balanced binary search tree.
"""
def sortedArrayToBST(self, nums: list[int]) -> Optional[TreeNode]:
if not nums:
return None
# set median arr as root
mid = (len(nums))//2
root = TreeNode(nums[mid])
#left subtree of root : val < nums[mid]
root.left = self.sortedArrayToBST(nums[:mid])
#right subtree of root : val > nums[mid]
root.right = self.sortedArrayToBST(nums[mid+1:])
return root
# extra function for displaying PreOrder Traversal of constructed BST
def preOrder(self, node : Optional[TreeNode]):
if not node:
return None
print(node.val)
self.preOrder(node.left)
self.preOrder(node.right)