Project Notes

Construct Binary Tree from Preorder and Inorder Traversal

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Description

tab: English
 
<p>Given two integer arrays <code>preorder</code> and <code>inorder</code> where <code>preorder</code> is the preorder traversal of a binary tree and <code>inorder</code> is the inorder traversal of the same tree, construct and return <em>the binary tree</em>.</p>
 
<p>&nbsp;</p>
<p><strong class="example">Example 1:</strong></p>
<img alt="" src="https://assets.leetcode.com/uploads/2021/02/19/tree.jpg" style="width: 277px; height: 302px;" />
<pre>
<strong>Input:</strong> preorder = [3,9,20,15,7], inorder = [9,3,15,20,7]
<strong>Output:</strong> [3,9,20,null,null,15,7]
</pre>
 
<p><strong class="example">Example 2:</strong></p>
 
<pre>
<strong>Input:</strong> preorder = [-1], inorder = [-1]
<strong>Output:</strong> [-1]
</pre>
 
<p>&nbsp;</p>
<p><strong>Constraints:</strong></p>
 
<ul>
	<li><code>1 &lt;= preorder.length &lt;= 3000</code></li>
	<li><code>inorder.length == preorder.length</code></li>
	<li><code>-3000 &lt;= preorder[i], inorder[i] &lt;= 3000</code></li>
	<li><code>preorder</code> and <code>inorder</code> consist of <strong>unique</strong> values.</li>
	<li>Each value of <code>inorder</code> also appears in <code>preorder</code>.</li>
	<li><code>preorder</code> is <strong>guaranteed</strong> to be the preorder traversal of the tree.</li>
	<li><code>inorder</code> is <strong>guaranteed</strong> to be the inorder traversal of the tree.</li>
</ul>
 
 
 
---
 
[submissions](https://leetcode.com/problems/construct-binary-tree-from-preorder-and-inorder-traversal/submissions/) | [solutions](https://leetcode.com/problems/construct-binary-tree-from-preorder-and-inorder-traversal/solutions/)
 
 
tab: 中文
 
<p>给定两个整数数组&nbsp;<code>preorder</code> 和 <code>inorder</code>&nbsp;，其中&nbsp;<code>preorder</code> 是二叉树的<strong>先序遍历</strong>， <code>inorder</code>&nbsp;是同一棵树的<strong>中序遍历</strong>，请构造二叉树并返回其根节点。</p>
 
<p>&nbsp;</p>
 
<p><strong>示例 1:</strong></p>
<img alt="" src="https://assets.leetcode.com/uploads/2021/02/19/tree.jpg" style="height: 302px; width: 277px;" />
<pre>
<strong>输入</strong><strong>:</strong> preorder = [3,9,20,15,7], inorder = [9,3,15,20,7]
<strong>输出:</strong> [3,9,20,null,null,15,7]
</pre>
 
<p><strong>示例 2:</strong></p>
 
<pre>
<strong>输入:</strong> preorder = [-1], inorder = [-1]
<strong>输出:</strong> [-1]
</pre>
 
<p>&nbsp;</p>
 
<p><strong>提示:</strong></p>
 
<ul>
	<li><code>1 &lt;= preorder.length &lt;= 3000</code></li>
	<li><code>inorder.length == preorder.length</code></li>
	<li><code>-3000 &lt;= preorder[i], inorder[i] &lt;= 3000</code></li>
	<li><code>preorder</code>&nbsp;和&nbsp;<code>inorder</code>&nbsp;均 <strong>无重复</strong> 元素</li>
	<li><code>inorder</code>&nbsp;均出现在&nbsp;<code>preorder</code></li>
	<li><code>preorder</code>&nbsp;<strong>保证</strong> 为二叉树的前序遍历序列</li>
	<li><code>inorder</code>&nbsp;<strong>保证</strong> 为二叉树的中序遍历序列</li>
</ul>
 
 
 
---
 
[提交记录](https://leetcode.cn/problems/construct-binary-tree-from-preorder-and-inorder-traversal/submissions/) | [题解](https://leetcode.cn/problems/construct-binary-tree-from-preorder-and-inorder-traversal/solution/)

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