mirror of
https://gitee.com/coder-xiaomo/leetcode-problemset
synced 2025-01-10 18:48:13 +08:00
27 lines
941 B
HTML
27 lines
941 B
HTML
<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> </p>
|
|
<p><strong>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>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> </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 <= Node.val <= 100</code></li>
|
|
</ul>
|
|
|
|
<p> </p>
|
|
<strong>Follow up:</strong> Could you solve it both recursively and iteratively? |