public class Solution
extends Object
513 - Find Bottom Left Tree Value\.
Medium
Given the `root` of a binary tree, return the leftmost value in the last row of the tree.
**Example 1:**
**Input:** root = [2,1,3]
**Output:** 1
**Example 2:**
**Input:** root = [1,2,3,4,null,5,6,null,null,7]
**Output:** 7
**Constraints:**
* The number of nodes in the tree is in the range [1, 104].
* -231 <= Node.val <= 231 - 1