Project Notes

Symmetric Tree

3 min read

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Description

tab: English
 
<p>Given the <code>root</code> of a binary tree, <em>check whether it is a mirror of itself</em> (i.e., symmetric around its center).</p>
 
<p>&nbsp;</p>
<p><strong class="example">Example 1:</strong></p>
<img alt="" src="https://assets.leetcode.com/uploads/2021/02/19/symtree1.jpg" style="width: 354px; height: 291px;" />
<pre>
<strong>Input:</strong> root = [1,2,2,3,4,4,3]
<strong>Output:</strong> true
</pre>
 
<p><strong class="example">Example 2:</strong></p>
<img alt="" src="https://assets.leetcode.com/uploads/2021/02/19/symtree2.jpg" style="width: 308px; height: 258px;" />
<pre>
<strong>Input:</strong> root = [1,2,2,null,3,null,3]
<strong>Output:</strong> false
</pre>
 
<p>&nbsp;</p>
<p><strong>Constraints:</strong></p>
 
<ul>
	<li>The number of nodes in the tree is in the range <code>[1, 1000]</code>.</li>
	<li><code>-100 &lt;= Node.val &lt;= 100</code></li>
</ul>
 
<p>&nbsp;</p>
<strong>Follow up:</strong> Could you solve it both recursively and iteratively?
 
 
---
 
[submissions](https://leetcode.com/problems/symmetric-tree/submissions/) | [solutions](https://leetcode.com/problems/symmetric-tree/solutions/)
 
 
tab: 中文
 
<p>给你一个二叉树的根节点 <code>root</code> ， 检查它是否轴对称。</p>
 
<p>&nbsp;</p>
 
<p><strong>示例 1：</strong></p>
<img alt="" src="https://pic.leetcode.cn/1698026966-JDYPDU-image.png" style="width: 354px; height: 291px;" />
<pre>
<strong>输入：</strong>root = [1,2,2,3,4,4,3]
<strong>输出：</strong>true
</pre>
 
<p><strong>示例 2：</strong></p>
<img alt="" src="https://pic.leetcode.cn/1698027008-nPFLbM-image.png" style="width: 308px; height: 258px;" />
<pre>
<strong>输入：</strong>root = [1,2,2,null,3,null,3]
<strong>输出：</strong>false
</pre>
 
<p>&nbsp;</p>
 
<p><strong>提示：</strong></p>
 
<ul>
	<li>树中节点数目在范围 <code>[1, 1000]</code> 内</li>
	<li><code>-100 &lt;= Node.val &lt;= 100</code></li>
</ul>
 
<p>&nbsp;</p>
 
<p><strong>进阶：</strong>你可以运用递归和迭代两种方法解决这个问题吗？</p>
 
 
 
---
 
[提交记录](https://leetcode.cn/problems/symmetric-tree/submissions/) | [题解](https://leetcode.cn/problems/symmetric-tree/solution/)

Solutions & Notes

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