# 找树左下角的值

<p>给定一个二叉树的 <strong>根节点</strong> <code>root</code>，请找出该二叉树的 <strong>最底层 最左边 </strong>节点的值。</p>

<p>假设二叉树中至少有一个节点。</p>

<p> </p>

<p><strong>示例 1:</strong></p>

<p><img src="https://assets.leetcode.com/uploads/2020/12/14/tree1.jpg" style="width: 182px; " /></p>

<pre>
<strong>输入: </strong>root = [2,1,3]
<strong>输出: </strong>1
</pre>

<p><strong>示例 2:</strong></p>

<p><img src="https://assets.leetcode.com/uploads/2020/12/14/tree2.jpg" style="width: 242px; " /><strong> </strong></p>

<pre>
<strong>输入: </strong>[1,2,3,4,null,5,6,null,null,7]
<strong>输出: </strong>7
</pre>

<p> </p>

<p><strong>提示:</strong></p>

<ul>
	<li>二叉树的节点个数的范围是 <code>[1,10<sup>4</sup>]</code></li>
	<li><meta charset="UTF-8" /><code>-2<sup>31</sup> <= Node.val <= 2<sup>31</sup> - 1</code> </li>
</ul>

<p>以下错误的选项是？</p>

## aop

### before

```cpp

```
### after

```cpp

```

## 答案

```cpp

```

## 选项


### A

```cpp

```

### B

```cpp

```

### C

```cpp

```
