► LeetCode 1302. Deepest Leaves Sum: https://leetcode.com/problems/deepest-leaves-sum/
► Problem açıklaması:
Given the root of a binary tree, return the sum of values of its deepest leaves.
Input: root = [1,2,3,4,5,null,6,7,null,null,null,null,8]
Input: root = [6,7,8,2,7,1,3,9,null,1,4,null,null,null,5]
The number of nodes in the tree is in the range [1, 104].
1 <= Node.val <= 100