# 两数之和

<p>给你一棵二叉树的根节点 <code>root</code> ，请你返回 <strong>层数最深的叶子节点的和</strong> 。</p>

<p> </p>

<p><strong>示例 1：</strong></p>

<p><strong><img alt="" src="https://assets.leetcode-cn.com/aliyun-lc-upload/uploads/2019/12/28/1483_ex1.png" style="height: 265px; width: 273px;" /></strong></p>

<pre>
<strong>输入：</strong>root = [1,2,3,4,5,null,6,7,null,null,null,null,8]
<strong>输出：</strong>15
</pre>

<p><strong>示例 2：</strong></p>

<pre>
<strong>输入：</strong>root = [6,7,8,2,7,1,3,9,null,1,4,null,null,null,5]
<strong>输出：</strong>19
</pre>

<p> </p>

<p><strong>提示：</strong></p>

<ul>
	<li>树中节点数目在范围 <code>[1, 10<sup>4</sup>]</code> 之间。</li>
	<li><code>1 <= Node.val <= 100</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

```
