Teardrop Forest Height

You are given one or more binary trees represented in level-order. In the level-order array, a value of -1 represents a null node. Your task is to compute the height of each binary tree.

The height of a binary tree is defined as follows. For an empty tree, \(height = 0\). Otherwise, \(height = 1 + \max(\text{height of left subtree},\, \text{height of right subtree})\).

You need to process multiple test cases.

inputFormat

The input is read from standard input (stdin) and has the following format:

• The first line contains an integer T representing the number of test cases.
• For each test case:
• The first line contains an integer N which is the number of nodes in the level-order traversal.
• If N is not zero, the next line contains N space-separated integers representing the level-order traversal of the tree. A value of -1 indicates a null node. If N equals 0, it means the tree is empty.

outputFormat

For each test case, output the height of the corresponding binary tree on a separate line to standard output (stdout).

## sample

2
9
1 2 3 -1 -1 4 5 -1 -1 -1 -1 6 7
7
1 2 3 -1 4 -1 5

4
3

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