Given a binary tree, return the bottom-left most value.

BottomLeftTreeValue.kt

fun findBottomLeftValue(root: TreeNode?): Int {
    val queue: Queue<TreeNode?> = LinkedList<TreeNode?>()
    queue.offer(root)
    var node: TreeNode? = queue.peek()
    while (queue.isNotEmpty()) {
        node = queue.poll()
        if (node?.right != null) {
            queue.add(node.right)
        }
        if (node?.left != null) {
            queue.add(node.left)
        }
    }
    return node?.`val` ?: -1
}

/*
Given the root of a binary tree, return the leftmost value in the last row of the tree.

Ex: Given the following binary tree…

      1
     / \
    2   3
   /
  4 
return 4.
Ex: Given the following binary tree…

      8
     / \
    1   4
       /
      2 
return 2.
* */

/**
 * @see [https://leetcode.com/problems/find-bottom-left-tree-value/](https://leetcode.com/problems/find-bottom-left-tree-value/)
 */