leetcode-problemset/leetcode-cn/problem (Chinese)/彩灯装饰记录 I [cong-shang-dao-xia-da-yin-er-cha-shu-lcof].html

<p>一棵圣诞树记作根节点为 <code>root</code> 的二叉树，节点值为该位置装饰彩灯的颜色编号。请按照从 <strong>左</strong> 到 <strong>右</strong> 的顺序返回每一层彩灯编号。</p>

<p>&nbsp;</p>

<p><strong>示例 1：</strong></p>

<p><img alt="" src="https://pic.leetcode.cn/1694758674-XYrUiV-%E5%89%91%E6%8C%87%20Offer%2032%20-%20I_%E7%A4%BA%E4%BE%8B1.png" /></p>

<pre>
<strong>输入：</strong>root = [8,17,21,18,null,null,6]
<strong>输出：</strong>[8,17,21,18,6]
</pre>

<p>&nbsp;</p>

<p><strong>提示：</strong></p>

<ol>
	<li><code>节点总数 &lt;= 1000</code></li>
</ol>

<p>&nbsp;</p>