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32 lines
1.4 KiB
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<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>
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<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> or any child of <code>a</code> is an ancestor of <code>b</code>.</p>
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<p> </p>
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<p><strong>Example 1:</strong></p>
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<img alt="" src="https://assets.leetcode.com/uploads/2020/11/09/tmp-tree.jpg" style="width: 400px; height: 390px;" />
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<pre>
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<strong>Input:</strong> root = [8,3,10,1,6,null,14,null,null,4,7,13]
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<strong>Output:</strong> 7
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<strong>Explanation: </strong>We have various ancestor-node differences, some of which are given below :
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|8 - 3| = 5
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|3 - 7| = 4
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|8 - 1| = 7
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|10 - 13| = 3
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Among all possible differences, the maximum value of 7 is obtained by |8 - 1| = 7.</pre>
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<p><strong>Example 2:</strong></p>
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<img alt="" src="https://assets.leetcode.com/uploads/2020/11/09/tmp-tree-1.jpg" style="width: 250px; height: 349px;" />
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<pre>
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<strong>Input:</strong> root = [1,null,2,null,0,3]
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<strong>Output:</strong> 3
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</pre>
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<p> </p>
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<p><strong>Constraints:</strong></p>
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<ul>
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<li>The number of nodes in the tree is in the range <code>[2, 5000]</code>.</li>
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<li><code>0 <= Node.val <= 10<sup>5</sup></code></li>
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</ul>
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