Given a binary tree, determine if it is height-balanced.

A height-balanced binary tree is a binary tree in which the heights of the left and right subtrees of every node never differ by more than one.

Example 1: Screenshot_2025-03-14_at_4.36.53_PM.png

Input: root = [13,20,17,null,null,10,16]
Output: true
Explanation: All subtrees have heights differing by at most 1.
Node 20 has a height difference of 0.
Node 17 has a height difference of 0.
Root node 13 has a left height of 1 and right height of 2 (difference = 1, within limits).

Example 2: Screenshot_2025-03-14_at_4.38.48_PM.png

Input: root = [1,2,7,8,6,11, 12]
Output: true
Explanation: All subtrees have heights differing by at most 1.

Example 3: Screenshot_2025-03-14_at_4.32.28_PM.png

Input: root = [1,2,3,5,null,null,null,4]
Output: false
Explanation: Node 2 is unbalanced because its left subtree has height 2 and its right subtree has height 0, so the difference is 2, which is greater than 1.

Constraints

The number of nodes in the tree is in the range [0, 5000].

-10⁴ <= Node.val <= 10⁴

24. Balanced Binary Tree