Given a Binary Tree of size N, find size of the Largest Independent Set(LIS) in it. A subset of all tree nodes is an independent set if there is no edge between any two nodes of the subset. Your task is to complete the function LISS(), which finds the size of the Largest Independent Set.
For example: Consider the following binary tree.The LIS is LIS: [10, 40, 60, 70, 80] Size: 5.
The function takes a single argument as input, the root of the binary tree. There will be T test cases and for each test case the function will be called separately.
For each test case function should return the size of the Largest Independent Set (LIS).
1 2 R 1 3 L
10 20 L 10 30 R 20 40 L 20 60 R
Note:The Input/Ouput format and Example given are used for system's internal purpose, and should be used by a user for Expected Output only. As it is a function problem, hence a user should not read any input from stdin/console. The task is to complete the function specified, and not to write the full code.