all-possible-full-binary-trees

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Algorithms

Given an integer <code>n</code>, return a list of all possible full binary trees with <code>n</code> nodes. Each node of each tree in the answer must have <code>Node.val == 0</code>.

Each element of the answer is the root node of one possible tree. You may return the final list of trees in any order.

A full binary tree is a binary tree where each node has exactly <code>0</code> or <code>2</code> children.

&nbsp;
Example 1:
<img alt="" src="https://s3-lc-upload.s3.amazonaws.com/uploads/2018/08/22/fivetrees.png" style="width: 700px; height: 400px;" />
<pre>
Input: n = 7
Output: [[0,0,0,null,null,0,0,null,null,0,0],[0,0,0,null,null,0,0,0,0],[0,0,0,0,0,0,0],[0,0,0,0,0,null,null,null,null,0,0],[0,0,0,0,0,null,null,0,0]]
</pre>

Example 2:

<pre>
Input: n = 3
Output: [[0,0,0]]
</pre>

&nbsp;
Constraints:

<ul>
	<li><code>1 &lt;= n &lt;= 20</code></li>
</ul>

allPossibleFBT

All Possible Full Binary Trees

Tree

Recursion

Memoization

Dynamic Programming

Binary Tree

给你一个整数 <code>n</code> ，请你找出所有可能含 <code>n</code> 个节点的 真二叉树 ，并以列表形式返回。答案中每棵树的每个节点都必须符合 <code>Node.val == 0</code> 。

答案的每个元素都是一棵真二叉树的根节点。你可以按 任意顺序 返回最终的真二叉树列表。

真二叉树 是一类二叉树，树中每个节点恰好有 <code>0</code> 或 <code>2</code> 个子节点。

&nbsp;

示例 1：
<img alt="" src="https://s3-lc-upload.s3.amazonaws.com/uploads/2018/08/22/fivetrees.png" style="width: 700px; height: 400px;" />
<pre>
输入：n = 7
输出：[[0,0,0,null,null,0,0,null,null,0,0],[0,0,0,null,null,0,0,0,0],[0,0,0,0,0,0,0],[0,0,0,0,0,null,null,null,null,0,0],[0,0,0,0,0,null,null,0,0]]
</pre>

示例 2：

<pre>
输入：n = 3
输出：[[0,0,0]]
</pre>

&nbsp;

提示：

<ul>
	<li><code>1 &lt;= n &lt;= 20</code></li>
</ul>