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24 lines
706 B
HTML
24 lines
706 B
HTML
<p>Given an integer <code>n</code>, return <em>the number of structurally unique <strong>BST'</strong>s (binary search trees) which has exactly </em><code>n</code><em> nodes of unique values from</em> <code>1</code> <em>to</em> <code>n</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/2021/01/18/uniquebstn3.jpg" style="width: 600px; height: 148px;" />
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<pre>
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<strong>Input:</strong> n = 3
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<strong>Output:</strong> 5
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</pre>
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<p><strong>Example 2:</strong></p>
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<pre>
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<strong>Input:</strong> n = 1
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<strong>Output:</strong> 1
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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><code>1 <= n <= 19</code></li>
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</ul>
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