SDE - 1

You have been given an undirected graph with 'N' vertices and 'M' edges. The vertices are labelled from 1 to 'N'.

Your task is to find if the graph contains a cycle or not.

A path that starts from a given vertex and ends at the same vertex traversing the edges only once is called a cycle.

Example :

In the below graph, there exists a cycle between vertex 1, 2 and 3. 

Note:

1. There are no parallel edges between two vertices.

2. There are no self-loops(an edge connecting the vertex to itself) in the graph.

3. The graph can be disconnected.

For Example :

Input: N = 3 , Edges =  [[1, 2], [2, 3], [1, 3]].
Output: Yes

Explanation : There are a total of 3 vertices in the graph. There is an edge between vertex 1 and 2, vertex 2 and 3 and vertex 1 and 3. So, there exists a cycle in the graph. 

You are given a string 'S' of length 'N' consisting of lowercase English alphabet letters. You are also given a positive integer 'K'.

Now, a substring of this string is good if it contains at most 'K' distinct characters. A string 'X' is a substring of string 'Y' if it can be obtained by deletion of several continuous elements(possibly zero) from the beginning and the end from the string 'Y'.

Your task is to return the maximum size of any good substring of the string 'S'.

Example:

‘S’ = “bacda” and ‘K’ = 3.

So, the substrings having at most ‘3’ distinct characters are called good substrings. Some possible good substrings are:
1. “bac”
2. “acd”
3. “acda”

The substring “acda” is the largest possible good substring, as we cannot get any other substring of length 5 or more having distinct characters less than or equal to ‘3’. Thus, you should return ‘4’ as the answer.

You have been given a binary tree of integers with N number of nodes. Your task is to check if that input tree is a BST (Binary Search Tree) or not.

A binary search tree (BST) is a binary tree data structure which has the following properties.

• The left subtree of a node contains only nodes with data less than the node’s data.
• The right subtree of a node contains only nodes with data greater than the node’s data.
• Both the left and right subtrees must also be binary search trees.

Example :

Answer :

Level 1: 

All the nodes in the left subtree of 4 (2, 1, 3) are smaller 
than 4, all the nodes in the right subtree of the 4 (5) are 
larger than 4.

Level 2 :

For node 2:
All the nodes in the left subtree of 2 (1) are smaller than 
2, all the nodes in the right subtree of the 2 (3) are larger than 2.
For node 5:
The left and right subtrees for node 5 are empty.

Level 3:

For node 1:
The left and right subtrees for node 1 are empty.
For node 3:
The left and right subtrees for node 3 are empty.

Because all the nodes follow the property of a binary search tree, the above tree is a binary search tree.

He asked me 4-5 SQL queries. 
Asked to implement Upsert functionality in Spark Dataframes,
Asked about optimizations I had used and was aware about, interanl implementation of thoese Optimization.

You are given an array 'ARR' of 'N' distinct positive integers. You are also given a non-negative integer 'B'.

Your task is to return all unique combinations in the array whose sum equals 'B'. A number can be chosen any number of times from the array 'ARR'.

Elements in each combination must be in non-decreasing order.

For example:

Let the array 'ARR' be [1, 2, 3] and 'B' = 5. Then all possible valid combinations are-

(1, 1, 1, 1, 1)
(1, 1, 1, 2)
(1, 1, 3)
(1, 2, 2)
(2, 3)

We are suffering from the Second wave of Covid-19. The Government is trying to increase its vaccination drives. Ninja wants to help the Government to plan an effective method to help increase vaccination following safety measures. Time is running out. Can you help the nation?

You are given two positive integers: ‘n,’ ‘maxVaccines’ denoting the number of days for which this vaccination drive will go on and the total number of vaccines available for the drive, respectively. You have to find the number of vaccines administered each day. You are also given a number ‘dayNumber,’ and we are interested to know the maximum number of vaccines that can be administered on ‘dayNumber’ th day.

The rules of the vaccination drive :

1. There should be a positive number of vaccines administered each day during the vaccination drive.

2. The absolute difference between the number of vaccines in two consecutive days should not exceed 1.

3. The sum of all the elements of the vaccines array does not exceed maxVaccines, that is, you cannot administer more vaccines than what is provided to you.

4. Vaccines administered on ‘dayNumber’ th day should be maximized.

Given an array/list of integers of length ‘N’, there is a sliding window of size ‘K’ which moves from the beginning of the array, to the very end. You can only see the ‘K’ numbers in a particular window at a time. For each of the 'N'-'K'+1 different windows thus formed, you are supposed to return the maximum element in each of them, from the given array/list.

He took a deep dig at my projects and asked me everything around my resume, after that he asked me a coding Question
He then asked me a SQL query on window functions and dense rank
In Spark in he asked me around the fundamentals and implementation of Broadcast Variables.

My Aspirations, How my team mates should be , How my Manager should be, Relationships with Manager,Relationships with Team members, Difficult scenario encoutered in the past, how did I overcome an unwinable situation.