Unival Trees Problem Statement

You are given a binary tree. Your task is to return the count of unival sub-trees in the given binary tree. In a unival tree, all nodes below the root node have the same value as the root node.

Example:

Consider the binary tree given in the following diagram, the number of unival trees is 5.

Input:

The first line of input contains an integer T, the number of test cases.

The next T lines, where each line contains elements in level order form. The input consists of values of nodes separated by a single space in a single line. In case a node is null, we take -1 in its place.

For example, the input for the tree depicted in the below image would be:
1
2 3
4 -1 5 6
-1 7 -1 -1 -1 -1
-1 -1

Output:

For every test case, print a single line containing an integer, i.e., the count of unival trees.

Example:

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

Output:
5

Constraints:

• 1 <= T <= 10
• 0 <= N <= 10^5
• 0 <= data <= 10^4, where data is the value for a node.
• Time Limit: 1 sec

Note:

The above format was just to provide clarity on how the input is formed for a given tree. The sequence will be put together in a single line separated by a single space. Hence, for the above depicted tree, the input will be given as:
1
1 2 3 4 -1 5 6 -1 7 -1 -1 -1 -1 -1 -1

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