1302. Deepest Leaves Sum

https://leetcode.com/problems/deepest-leaves-sum

Description

Given the root of a binary tree, return the sum of values of its deepest leaves. Example 1:

**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 [1, 104].

• 1 <= Node.val <= 100

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