Binary search tree

Given a node, validate the binary search tree, ensuring that every node's left hand child is less than the parent node's value, and that every node's right hand child is greater than the parent

Requirements that are always true for any given node in Binary Search Tree:

• parent node value is always greater than value of all nodes in the left subtree
  and less than value of all nodes in the right subtree
• left node value is also a valid BST
• right node value is also a valid BST

Challenge | Solution

val tree = Node(2)
tree.insert(10)
isValidSearchBinaryTree(tree) // true