Height of Binary Tree

You are given an arbitrary binary tree consisting of N nodes where each node is associated with a certain value. You need to find out the height of the tree.

Height of a binary tree is the maximum number of edges fee traverse from the root to one of the leaf nodes.

Input Format :

The first line of the input contains a single integer T, representing the number of test cases. 

The first line of each test case will contain the values of the tree’s nodes in the level order form ( -1 for NULL node). Refer to the example for further clarification.

Example :

Consider the binary tree

The input of the tree depicted in the image above will be like: 

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

Explanation :
Level 1 :
The root node of the tree is 1

Level 2 :
Left child of 1 = 2
Right child of 1 = 3

Level 3 :
Left child of 2 = 4
Right child of 2 = null (-1)
Left child of 3 = 5
Right child of 3 = 6

Level 4 :
Left child of 4 = null (-1)
Right child of 4 = 7
Left child of 5 = null (-1)
Right child of 5 = null (-1)
Left child of 6 = null (-1)
Right child of 6 = null (-1)

Level 5 :
Left child of 7 = null (-1)
Right child of 7 = null (-1)

The first not-null node (of the previous level) is treated as the parent of the first two nodes of the current level. The second not-null node (of the previous level) is treated as the parent node for the next two nodes of the current level and so on.

The input ends when all nodes at the last level are null (-1).

Output Format :

For each test case, the print height of the given binary tree. 

Note :

You do not need to print anything. It has already been taken care of. Just implement the given function.

Constraints :

1 <= T <= 5
1 <= N <= 3000

Time Limit: 1sec

Sample Input 1:

2 3 1 2 -1 -1 -1 -1 3 -1 1 2 -1 -1 -1

Sample Output 1:

1 2

Explanation for sample input 1:

For the first test case, the given tree is :

For each child left or right or node, we have the utmost one node so height is 1.

For the second test case, the given tree is

The root node has only a right node and the right node has only one node which is the left node so total of two nodes are there so the height is 2.