Solution: Validate Binary Search Tree

Problem Statement

Determine if a given binary tree is a binary search tree (BST). In a BST, for each node:

• All nodes to its left have values less than the node's value.
• All nodes to its right have values greater than the node's value.

Example Generation

Example 1:

• Input: [5,3,7]
• Expected Output: true
• Justification: The left child of the root (3) is less than the root, and the right child of the root (7) is greater than the root. Hence, it's a BST.

Example 2:

• Input: [5,7,3]
• Expected Output: false