Binary Tree Level Order Traversal

Given a binary tree of integers, return the level order traversal of the tree in a single line for each test case.

Input:

The input consists of multiple test cases as described:

The first line is an integer 'T', representing the number of test cases. For each test case, one line contains the elements of the tree in level order, where ‘-1’ signifies a null node.

Output:

Print the nodes in level order traversal, separated by a single space, for each test case.

Example:

Input:

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

Output:

1 2 3 4 5 6 7

Explanation:

The level order traversal visits nodes level by level from left to right. Therefore, the output for the binary tree is a single line of node values in their visited order.

Constraints:

• 1 ≤ T ≤ 100
• 0 ≤ N ≤ 1000
• 0 ≤ data ≤ 10⁶ and data ≠ -1

Where 'T' is the number of test cases, 'N' is the total number of nodes, and 'data' is the node value.

Time Limit: 1 second

Note:

The actual implementation does not require any printing. It is sufficient to implement the function logic and return the result.