Validate Binary Search Tree Problem Statement

Your task is to determine if a given binary tree with 'N' nodes is a valid Binary Search Tree (BST). A BST is defined by the following properties:

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

Input:

The input consists of multiple test cases. Each test case provides the level order traversal of the binary tree as follows:

The first line contains an integer 'T', the number of test cases.
Each test case contains a line with space-separated integers representing the values of nodes in level order. A value of -1 indicates a null node in the tree.

Output:

For each test case, output 'true' if the binary tree is a BST, otherwise output 'false'. Each result is displayed on a new line.

Example:

Input:

1
1 2 3 4 -1 5 6 -1 7 -1 -1 -1 -1 -1 -1

Output:

false

Constraints:

• 1 ≤ T ≤ 100
• 1 ≤ N ≤ 5000
• -10⁶ <= data ≤ 10⁶, and data ≠ -1

Note:

You are only required to implement the validation function for a BST. The input and output are managed elsewhere.