SDE - 1

Bob has been given a binary tree having N nodes. He has been asked to check if all the leaf nodes are at the same level.

Your task is to help Bob in checking if all the leaf nodes are at the same level or not. Return true if all the leaf nodes are at the same level otherwise return false.

A binary tree is a hierarchical data structure in which each node has at most two children.

Any node whose left and right child are null is called a leaf node in a binary tree.

Example:

Consider the given binary tree:

For the given tree the leaf nodes are 5, 4, 7, 6. All these nodes are on the same level. So the output will be True. 

Given an integer array ‘arr’ of length ‘n’, return the number of longest increasing subsequences in it.

The longest increasing subsequence(LIS) is the longest subsequence of the given sequence such that all subsequent elements are in strictly increasing order.

Example:

Input: ‘n’ = 5, ‘arr’ = [50, 3, 90, 60, 80].

Output: 2

Explanation: 
In this array, the longest increasing subsequences are [50, 60, 80] and [3, 60, 80]. 

There are other increasing subsequences as well, but we need the number of the longest ones. Hence the answer is 2.

You are given a ‘root’ of the binary tree, and you have to return the sum of all nodes present at the Kth level from the top. The root node is considered as level 1, and below it is level 2, and so on.

Note:

A binary tree is a tree in which each node has at most 2 children.

Example:

For Example, the root node is given as follows :
‘ROOT’ = 1 2 3 4 -1 -1 5 -1 -1 -1 -1 and ‘K’ = 2, Then the sum of all nodes at K-level will be 5. This is because 2 and 3 are present at level 2 and 2 + 3 = 5. Therefore 5 is the answer.

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He asked me to fill the numbers from 1 to 8 in these 8 boxes, one number exactly once, such that no two consecutive elements are
adjacent (diagonally, horizontally or vertically) to each other.

He asked about CPU scheduling algorithms. (Learn)
Difference between preemptive and non- preemptive algorithms. (Learn)
Round Robin algorithm. (Learn)
What is polymorphism? (Learn)
Difference between overloading and overriding. (Learn)

Implement a Queue Data Structure specifically to store integer data using a Singly Linked List or an array.

You need to implement the following public functions :

1. Constructor: It initializes the data members as required.

2. enqueue(data): This function should take one argument of type integer. It enqueues the element into the queue.

3. dequeue(): It dequeues/removes the element from the front of the queue and in turn, returns the element being dequeued or removed. In case the queue is empty, it returns -1.

4. front(): It returns the element being kept at the front of the queue. In case the queue is empty, it returns -1.

5. isEmpty(): It returns a boolean value indicating whether the queue is empty or not.

Operations Performed on the Queue :

Query-1(Denoted by an integer 1): Enqueues integer data to the queue.

Query-2(Denoted by an integer 2): Dequeues the data kept at the front of the queue and returns it to the caller, return -1 if no element is present in the queue.

Query-3(Denoted by an integer 3): Fetches and returns the data being kept at the front of the queue but doesn't remove it, unlike the dequeue function, return -1 if no element is present in the queue.

Query-4(Denoted by an integer 4): Returns a boolean value denoting whether the queue is empty or not.