leetcode_gym/_problems/convertSortedArrayToBST.md

layout, title, last_solved, category, leetcode_url, status

layout	title	last_solved	category	leetcode_url	status
page	Convert Sorted Array to Binary Search Tree			https://leetcode.com/problems/convert-sorted-array-to-binary-search-tree/	Attempted

Problem

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.

Example:

Given the sorted array: [-10,-3,0,5,9],

One possible answer is: [0,-3,9,-10,null,5], which represents the following height balanced BST:

      0
     / \
   -3   9
   /   /
 -10  5

Solution

{% highlight python %}

def sortedArrayToBST(self, nums: List[int]) -> TreeNode:

def buildTree(nums, left, right):
    
    if left>right: return
    
    mid = (left+right) // 2
    
    node = TreeNode(nums[mid])
    
    node.left = buildTree(nums, left, mid-1)
    node.right = buildTree(nums, mid+1, right)
    
    return node

if not nums: return None

return buildTree(nums, 0, len(nums)-1)

{% endhighlight %}