1302\. Deepest Leaves Sum

Medium

Given the `root` of a binary tree, return _the sum of values of its deepest leaves_.

**Example 1:**

![](https://assets.leetcode.com/uploads/2019/07/31/1483_ex1.png)

**Input:** root = [1,2,3,4,5,null,6,7,null,null,null,null,8]

**Output:** 15

**Example 2:**

**Input:** root = [6,7,8,2,7,1,3,9,null,1,4,null,null,null,5]

**Output:** 19

**Constraints:**

*   The number of nodes in the tree is in the range <code>[1, 10<sup>4</sup>]</code>.
*   `1 <= Node.val <= 100`