MTS-2

You are given the root node of a binary tree consisting of ‘N’ nodes. Your task is to find the number of good nodes in the given binary tree.

A good node is defined as good if there are no nodes with a value greater than X’s value in the path from the root to X.

You are given a root node ‘ROOT’.Your task is to return the number of good nodes.

Example:

Elements are in the 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

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).

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

Given two variables ‘X’ and ‘Y’. Your task is to swap the number without using a temporary variable or third variable.

Swap means the value of ‘X’ and ‘Y’ must be interchanged. Take an example ‘X’ is 10 and ‘Y’ is 20 so your function must return ‘X’ as a 20 and ‘Y’ as a 10.

You are given two non-negative numbers 'num1' and 'num2' represented in the form of linked lists.

The digits in the linked lists are stored in reverse order, i.e. starting from least significant digit (LSD) to the most significant digit (MSD), and each of their nodes contains a single digit.

Calculate the sum of the two numbers and return the head of the sum list.

Example :

Input:
'num1' : 1 -> 2 -> 3 -> NULL
'num2' : 4 -> 5 -> 6 -> NULL

Output: 5 -> 7 -> 9 -> NULL

Explanation: 'num1' represents the number 321 and 'num2' represents 654. Their sum is 975.