Inorder Traversal of Binary Tree

You are provided with a binary tree consisting of 'N' nodes, where each node carries an integer value. Your task is to determine the in-order traversal of the given binary tree.

Example:

Input:

For the given binary tree:
1 3 8 5 2 7 -1 -1 -1 -1 -1 -1 -1

Output:

The Inorder traversal will be [5, 3, 2, 1, 7, 4, 6].

Explanation:

The input represents the level order traversal of the binary tree. Each level is denoted consecutively, and a '-1' symbolizes a null node. For example:

[
Level 1: 1
Level 2: 3 8
Level 3: 5 2 7 -1
]

Constraints:

• 1 <= T <= 10
• 0 <= N <= 3000
• 0 <= data <= 10^9
• Time limit: 1 second

Input:

The first line contains an integer 'T' which denotes the number of test cases.
The first line of each test case contains elements of the tree in level order. Values of nodes are separated by a single space, with -1 representing a null node.

Output:

For each test case, return a vector containing the in-order traversal as space-separated integers.

Note:

 
 
  
No need to print the output, focus on implementing the function to return results.
 
  
The input terminates when all elements at the lowest level are null (-1).