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1026-maximum-difference-between-node-and-ancestor/README.md

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+<h2><a href="https://leetcode.com/problems/maximum-difference-between-node-and-ancestor/">1026. Maximum Difference Between Node and Ancestor</a></h2><h3>Medium</h3><hr><div><p>Given the <code>root</code> of a binary tree, find the maximum value <code>v</code> for which there exist <strong>different</strong> nodes <code>a</code> and <code>b</code> where <code>v = |a.val - b.val|</code> and <code>a</code> is an ancestor of <code>b</code>.</p>
+
+<p>A node <code>a</code> is an ancestor of <code>b</code> if either: any child of <code>a</code> is equal to <code>b</code>&nbsp;or any child of <code>a</code> is an ancestor of <code>b</code>.</p>
+
+<p>&nbsp;</p>
+<p><strong class="example">Example 1:</strong></p>
+<img alt="" src="https://assets.leetcode.com/uploads/2020/11/09/tmp-tree.jpg" style="width: 400px; height: 390px;">
+<pre><strong>Input:</strong> root = [8,3,10,1,6,null,14,null,null,4,7,13]
+<strong>Output:</strong> 7
+<strong>Explanation: </strong>We have various ancestor-node differences, some of which are given below :
+|8 - 3| = 5
+|3 - 7| = 4
+|8 - 1| = 7
+|10 - 13| = 3
+Among all possible differences, the maximum value of 7 is obtained by |8 - 1| = 7.</pre>
+
+<p><strong class="example">Example 2:</strong></p>
+<img alt="" src="https://assets.leetcode.com/uploads/2020/11/09/tmp-tree-1.jpg" style="width: 250px; height: 349px;">
+<pre><strong>Input:</strong> root = [1,null,2,null,0,3]
+<strong>Output:</strong> 3
+</pre>
+
+<p>&nbsp;</p>
+<p><strong>Constraints:</strong></p>
+
+<ul>
+	<li>The number of nodes in the tree is in the range <code>[2, 5000]</code>.</li>
+	<li><code>0 &lt;= Node.val &lt;= 10<sup>5</sup></code></li>
+</ul>
+</div>