Validate Binary Search Tree is an example of Tree problems. In this post we will see how we can solve in Javascript.

Problem Description

Given a binary tree, determine if it is a valid binary search tree (BST). Assume a BST is defined as follows:

  • The left subtree of a node contains only nodes with keys less than the node's key.
  • The right subtree of a node contains only nodes with keys greater than the node's key.
  • Both the left and right subtrees must also be binary search trees.

Example 1:

      2
     / \
    1   3

Binary tree [2,1,3], return true.

 Example 2:

      1
     / \
    2   3

Binary tree [1,2,3], return false.

Please check the main.js snippet for the solution.

If you have different approach in mind or have any suggestion for this implementation feel free to share in the comment below. Thanks!