balanced-binary-tree.html

<p>Given a binary tree, determine if it is height-balanced.</p>

<p>For this problem, a height-balanced binary tree is defined as:</p>

<blockquote>
<p>a binary tree in which the left and right subtrees of <em>every</em> node differ in height by no more than 1.</p>
</blockquote>

<p>&nbsp;</p>
<p><strong>Example 1:</strong></p>
<img alt="" src="https://assets.leetcode.com/uploads/2020/10/06/balance_1.jpg" style="width: 342px; height: 221px;" />
<pre>
<strong>Input:</strong> root = [3,9,20,null,null,15,7]
<strong>Output:</strong> true
</pre>

<p><strong>Example 2:</strong></p>
<img alt="" src="https://assets.leetcode.com/uploads/2020/10/06/balance_2.jpg" style="width: 452px; height: 301px;" />
<pre>
<strong>Input:</strong> root = [1,2,2,3,3,null,null,4,4]
<strong>Output:</strong> false
</pre>

<p><strong>Example 3:</strong></p>

<pre>
<strong>Input:</strong> root = []
<strong>Output:</strong> true
</pre>

<p>&nbsp;</p>
<p><strong>Constraints:</strong></p>

<ul>
	<li>The number of nodes in the tree is in the range <code>[0, 5000]</code>.</li>
	<li><code>-10<sup>4</sup> &lt;= Node.val &lt;= 10<sup>4</sup></code></li>
</ul>