unique-binary-search-trees

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Algorithms

Given an integer <code>n</code>, return the number of structurally unique BST&#39;s (binary search trees) which has exactly <code>n</code> nodes of unique values from <code>1</code> to <code>n</code>.

&nbsp;
Example 1:
<img alt="" src="https://assets.leetcode.com/uploads/2021/01/18/uniquebstn3.jpg" style="width: 600px; height: 148px;" />
<pre>
Input: n = 3
Output: 5
</pre>

Example 2:

<pre>
Input: n = 1
Output: 1
</pre>

&nbsp;
Constraints:

<ul>
	<li><code>1 &lt;= n &lt;= 19</code></li>
</ul>

numTrees

Unique Binary Search Trees

Unique Binary Search Trees II

unique-binary-search-trees-ii

不同的二叉搜索树 II

Tree

Binary Search Tree

Math

Dynamic Programming

Binary Tree

给你一个整数 <code>n</code> ，求恰由 <code>n</code> 个节点组成且节点值从 <code>1</code> 到 <code>n</code> 互不相同的 二叉搜索树 有多少种？返回满足题意的二叉搜索树的种数。

 

示例 1：
<img alt="" src="https://assets.leetcode.com/uploads/2021/01/18/uniquebstn3.jpg" style="width: 600px; height: 148px;" />
<pre>
输入：n = 3
输出：5
</pre>

示例 2：

<pre>
输入：n = 1
输出：1
</pre>

 

提示：

<ul>
	<li><code>1 <= n <= 19</code></li>
</ul>