Validate Partial Binary Search Tree (BST) Problem Statement

You are provided with a binary tree containing 'N' nodes. Your task is to determine if this tree is a Partial Binary Search Tree (BST). Return true if it is a Partial BST, otherwise return false.

Definition of a Partial BST:

• Each node's left subtree contains nodes with data less than or equal to the node's data.
• Each node's right subtree contains nodes with data greater than or equal to the node's data.
• Both left and right subtrees must be partial binary search trees themselves.

Example:

Input:

Output:

true

Explanation:

Level 1: All nodes in the left subtree of 4 (2, 1, 3) are smaller than 4, and those in the right subtree (5) are larger than 4.
Level 2: 
- For node 2: All nodes in its left subtree (1) are smaller than 2, and those in the right subtree (3) are larger than 2.
- For node 5: Both left and right subtrees are empty.
Level 3:
- For nodes 1 and 3, both left and right subtrees are empty.
Since all nodes follow the Partial BST properties, the tree is a Partial BST.

Input Format:

The first line contains an integer 't', the number of test cases. 
Each test case consists of a single line representing the tree's level order traversal, separated by spaces. Use '-1' to represent a null node. 
Example: '1 2 3 4 -1 5 6 -1 7 -1 -1 -1 -1 -1 -1'

Output Format:

Return 'true' or 'false' for each test case as a separate line.

Constraints:

• 1 <= T <= 100
• 1 <= N <= 1000
• -10^6 <= data <= 10^6
• Duplicate elements can be in either or both subtrees.
• Time Limit: 1 sec

Note:

Do not print anything under normal operations. Implement the function as described in the problem statement.