Trading Technologies SDE-2 Interview Questions and Answers

Round duration - 45 minutes
Round difficulty - Medium

Technical Interview round that lasted for about 45 minutes. Questions were based on Java, Java design Patterns and OOPS Concepts.

Q1. Java Question
What are static methods in Interfaces?
Ans. 
Static methods are useful for designing utility methods since they contain method implementation that is owned by the interface and invoked using the interface name. They cannot be overridden.
Answered by CodingNinjas
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Q2. Java Question
Why was a new version of Java (Java 8) needed in the first place? (
Ans. 
There are two primary reasons for this:
1. Due to significant developments in hardware, Java now needs to make better use of multi-core CPUs.
2. Make new Functional Programming (FP) features available to users.
Answered by CodingNinjas
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Q3. Java Question
What is a default method, and when does it get used?
Ans. 
The default method is found in the interface and involves an implementation. The technique extends an interface's functionality while maintaining backward compatibility with existing classes that implement the interface.
Answered by CodingNinjas
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Q4. Java Question
Describe in how many ways can you create a singleton pattern?
Ans. 
There are two ways of creating a Singleton pattern.
1. Early Instantiation : It is responsible for the creation of instance at load time.
2. Lazy Instantiation : It is responsible for the creation of instance when required.
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Round duration - 60 minutes
Round difficulty - Medium

Technical Interview round that lasted for about 45 minutes. Questions were based on Spring boot and Microservices Concepts.

Q1. Java Question
Difference between Bridge Pattern and Adapter Button
Ans. 
The motive of the Adapter pattern is to make interfaces of one or more classes to look similar. The Bridge pattern is designed to isolate a class's interface from its implementation so we can vary or substitute the implementation without changing the client code.
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Q2. SpringBoot Question
What is the difference between @RestController and @Controller in Spring Boot?
Ans. 
@Controller Map of the model object to view or template and make it human readable but @RestController simply returns the object and object data is directly written in HTTP response as JSON or XML.
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Q3. Technical Question
Difference between Spring and Spring Boot
Ans. 
1. Spring framework is a java EE framework that is used to build applications. Spring Boot framework is mainly used to develop REST API’s
2. The primary feature of the Spring framework is dependency injection. The main feature of the Spring Boot is Autoconfiguration. 
3. The goal pf Spring is to make Java EE (Enterprise Edition) development easier, allowing developers to be more productive. Spring Boot provides the ...read more
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Q4. Technical Question
Difference between Monolithic and Microservices Architecture
Ans. 
Monolithic Architecture: It is "like a big container" where all the software components of an application are bundled together tightly. It is usually built as one large system and is one code-base. 
Microservice Architecture: It involves structuring an application in the form of a cluster of small, autonomous services modeled around a business domain. The functional modules can be deployed independently, are scalab...read more
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Round duration - 30 minutes
Round difficulty - Easy

This was a typical HR round with some standard Behavioral questions

Q1. Basic HR Question
Why should we hire you ?
Ans. 
Tip 1 : The cross questioning can go intense some time, think before you speak.
Tip 2 : Be open minded and answer whatever you are thinking, in these rounds I feel it is important to have opinion.
Tip 3 : Context of questions can be switched, pay attention to the details. It is okay to ask questions in these round, like what are the projects currently the company is investing, which team you are mentoring. How all is the...read more
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Round duration - 60 minutes
Round difficulty - Medium

2 coding question both and 15 MCQ

Only C , Java , Python are allowed

Q1. Minimum steps to reach target by a Knight
You have been given a square chessboard of size ‘N x N’. The position coordinates of the Knight and the position coordinates of the target are also given.
Your t...read more
Ans.  Using BFS
The idea is to perform BFS traversal. Start from the initial position of the Knight and proceed to further cells. Traversal is performed using a queue. The queue stores the different paths travelled by the knight and also keeps storing the count of steps. When the target is popped from the queue, the corresponding count of the steps is the answer.
 
1. Define a class with the following data members
     &nbs...read more
Answered by CodingNinjas
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Q2. Maximum Size Rectangle Sub-matrix With All 1's
You are given an 'N' * 'M' sized binary-valued matrix 'MAT, where 'N' is the number of rows and 'M' is the number of colum...read more
Ans. Dynamic Programming.
1. We start from the first row and move downwards.
2. We create three 1-dimensional arrays HEIGHT[], LEFT[], RIGHT[].
3. ‘HEIGHT’[i]: stores the number of current continuous 1’s in column i.
4. LEFT[i] : stores the leftmost index ‘j’ such that all indices say ‘K’, ‘K’ belongs to [j, i], ‘HEIGHT’[k] >= ‘HEIGHT’[i].
5. RIGHT [i]: stores the rightmost index ‘j’ such that all indices say ‘K’, ‘K’ belongs to [i, j], ‘HE...read more
Answered by CodingNinjas
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Round duration - 45 minutes
Round difficulty - Easy

Around 6 am morning
2 interviewers

Q1. Reverse Linked List
You are given a Singly Linked List of integers. You need to reverse the Linked List by changing the links between nodes.
Input Format :
The first line of input contains a single integ...read more
Ans. Recursive Approach
One way is to use recursion to reverse the list. Divide the linked list in two halves, the first node and the rest of the list. Reverse the second half using recursion and append the first half, that is the first node at the end of the reversed linked list. Return the head of the reversed linked list.
 
Algorithm
 
• If the list contains only one node, return the head of the list.
• Else, divide the ...read more
Answered by CodingNinjas
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Q2. OS Question
Synchronization in Operating System in detail
Ans. 
Tip 1 : Go through Semaphore extremely important 
Answered by CodingNinjas
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Q3. Networking Question
Osi model with example at each layer transfer
Ans. 
Tip 1 : they will ask question in between make sure u explain it in very detail and give example live like how this interview is happening online with each layer playing its role.
Answered by CodingNinjas
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Q4. Networking Question
What is NAT router?
Ans. 
Tip 1 : Network address translation router
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Q5. Technical Question
How do beat Google if u want to make a search engine?
Ans. 
Tip 1 : I took this question to system design horizontal and vertical scaling which they agreed
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Q6. Puzzle
Total water in earth ?
Ans. 
Tip 1 : I said that i know earth radius , will calculate its surface area and multiple with average depth of water bodies in earth , they didn't respond.
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Round duration - 30 minutes
Round difficulty - Easy

Manager Round

Q1. Puzzle
It was all on my master's thesis
Ans. 
Tip 1 : Make sure if u project is working put its link preferably video of the working project my project was on ML and IOT and I put a Video link .
Answered by CodingNinjas
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Round duration - 10 Minutes
Round difficulty - Easy

Salary breakdown and Location preference

Q1. Basic HR Question
Are u satisfied with the salary breakup?
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Q2. Basic HR Question
Location preferences: banglore, chennai, Pune
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Amazon Online assessment which consisted of 2 coding DSA medium question

Q1. Question related to TreeMap
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Q2. Question related BFS
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Q3. System Design - Design Feed system
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Diameter of a binary tree and bfs and dfs questions

Data structure and algorithms

Q1. System design questions
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Q1. Behavioural questions related to leadership principle.
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Round duration - 60 Minutes
Round difficulty - Medium

Timing: 10AM-11AM
Interviewer was quite supportive and helpful.
Environment was normal as usual and it was morning time

Q1. Application Question
Design a system where user can upload, delete and share the video/image files. 
And can immediately view the uploaded files on the different logged-in system
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Round duration - 60 Minutes
Round difficulty - Medium

Timing: 11AM-12PM
The interviewer was SDE2
He was checking the code for edge cases and was hinting if required

Q1. Implement a priority queue
Ninja is given a task to implement a priority queue using Heap data structure. The Ninja is busying preparing for the tournament., So he asked for your help.
Your task is to us...read more
Ans. Array representation of heap
 
1. Since the heap is maintained in the form of a complete binary tree, the heap can be easily represented in the form of an array.
2. To keep the tree complete and shallow, while inserting a new element insert it in the leftmost vacant position in the last level i.e., at the end of our array, and perform some operation to maintain the property of the heap.
3. Similarly, for deleting the maximum e...read more
Answered by CodingNinjas
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Q2. Ninja and the bulbs
Ninja owns an electronic shop. In the shop, Ninja has 'N' bulbs. To sell these bulbs, Ninja has to check if they are of good quality. To check bulbs, Ninja uses a unique techniq...read more
Ans.  Brute Force
Approach:
A brute force solution to this problem is to turn on and off the bulbs N time, then at last check the number of bulbs that are on.

 
Algorithm:
• Take a boolean array of ‘BULBS’ of size N+1.
• Itertate on ‘i’ from 1 to ‘N’
  • Iterate on ‘j’ form ‘i’ to ‘N’ and each time increment ‘j’ as ‘j’ += ‘i’.
    • if(BULBS[j] == true) then make it false.
    • If (BULBS[j]==false) then make it true.
• Intialise a variable ‘COUNT’ =...read more
Answered by CodingNinjas
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Round duration - 60 Minutes
Round difficulty - Medium

Timing: 6PM-7PM
The interviewer was not interactive and didn't gave any feedback whatsoever.
It was Hiring Manager Round
Interviewer was Software Development Manager at Amazon

Q1. Maximize the sum
You are given two sorted arrays of distinct integers, ‘ARR1’ and ‘ARR2’. If you find a common element in both arrays, you can switch from one array to another.
Your task is to find a pat...read more
Ans. Recursive
In this problem, our primary focus is on the common elements i.e. an element that is present in both the arrays. Then, we have to decide whether we have to make a switch. So for that, first we store all the elements of ‘ARR1’ and ‘ARR2’ into ‘MAP1’ and ‘MAP2’ respectively. 
 
Now we call our ‘maximiseSumHelper’ function. We call this function for both cases i.e starting with ‘ARR1’ and starting with ‘A...read more
Answered by CodingNinjas
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Round duration - 60 minutes
Round difficulty - Easy

Started with brief intro(5 mins) about interviewer.
Problem solving question, question was already there in the codelink shared by the interviewer. He explained the problem again with sample testcase. 
The Interviewer was friendly.

Q1. Course Schedule II
You have been given ‘N’ courses and some courses may have prerequisites. Now consider a matrix ‘PREREQUISITES’ of size 'M' x 2 which represents that you must complete course '...read more
Ans. Breadth-First Search
Our current algorithm is based on the idea of the BFS approach. We first process all the courses with 0 in-degree implying no prerequisite courses required. If we remove all these courses from the graph, along with their outgoing edges, we can find out the courses/nodes that should be processed next. These would again be the nodes with 0 in-degree. We can continuously do this until all the courses h...read more
Answered by CodingNinjas
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Q2. System Design
System design a live video broadcast platform.
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Round duration - 90 minutes
Round difficulty - Medium

There were 2 interviewers(India HM and Seattle HM), India HM was just shadowing and didn't ask any questions. Started with intro, he asked in detail about what I do at current company(10 mins). Again, jumped into LP's(25 mins).

Q1. Distance between two nodes of a Tree
Given a binary tree and the value of two nodes, find the distance between the given two nodes of the Binary Tree.
Distance between two nodes is defined as the minimum...read more
Ans. Naive Approach
In any rooted tree, the distance between two nodes 'U' and 'V' can be found by finding the lowest common ancestor (LCA), ‘x’ of two nodes. The lowest common ancestor (LCA) between nodes 'U' and 'V' is defined as the lowest node in the tree that has both 'U' and 'V' as descendants, where we define each node to be a descendant of itself (so if 'U' has a direct connection from 'V', 'V' is the lowest common a...read more
Answered by CodingNinjas
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Q2. Median in a stream
Given that integers are read from a data stream. Your task is to find the median of the elements read so far.
Median is the middle value in an ordered integer list. If the size of the ...read more
Ans. Brute force approach
Store the incoming data elements in a vector. Sort the vector everytime you need to output the median.
Algorithm:
1. Store the incoming elements of the data stream in a vector.
2. Step by step insert one element and sort the vector as soon as any element is added in the vector.
3. If the size of the vector is odd, print the middle element of the sorted vector.
   If the size of the vector is even, return the mean of...read more
Answered by CodingNinjas
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Round duration - 60 minutes
Round difficulty - Medium

There was only 1 interviewer in this round and We had no video sharing in this round so it was becoming difficult to understand each other.

Q1. Object Oriented Design Question
Started with brief intro about both(5 mins), then he jumped into LP's(25 mins). This was very difficult since there was no video and he was grilling me real hard on this, so...read more
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Round duration - 45 minutes
Round difficulty - Medium

This round was scheduled in the evening hours and all the participants were required to fill a form which was shared 15 minutes prior to the start of the online coding round. This form was filled out probably for the security reasons and to ensure that no one disinterested participant gives the test.

Q1. Ways To Make Coin Change
You are given an infinite supply of coins of each of denominations D = {D0, D1, D2, D3, ...... Dn-1}. You need to figure out the total number of ways W, in which you can make a cha...read more
Ans. Recursion
 
1. The idea is to use recursion.
2. For a particular coin, we have two options either include it or exclude it.
3. If we include that coin, then calculate the remaining number that we have to generate so recur for that remaining number.
4. If we exclude that coin, then recur for the same amount that we have to make.
5. Our final answer would be the total number of ways either by including or excluding.
6. There will be two edg...read more
Answered by CodingNinjas
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Q2. Validate BST
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 tr...read more
Ans. BST property
The approach is based on the fact that the value of each node in a BST is greater than the value of all the nodes in the left subtree and smaller than the value of all the nodes in the right subtree.
 
Here is the complete algorithm-
• For each node, we store the minimum and maximum value allowed for that node. Initially, for the root node, the minimum value would be -10^9 and the maximum value should be 10...read more
Answered by CodingNinjas
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Round duration - 60 minutes
Round difficulty - Hard

This round was on call where I was just supposed to answer the tech questions that were asked. It started with a brief interview with one another and then moved to questions on DBMS, operating systems, computer networks and all. Almost 20-25 questions were asked and I probably answered 90% of them correctly.

Q1. Reverse Linked List
You are given a Singly Linked List of integers. You need to reverse the Linked List by changing the links between nodes.
Input Format :
The first line of input contains a single integ...read more
Ans. Recursive Approach
One way is to use recursion to reverse the list. Divide the linked list in two halves, the first node and the rest of the list. Reverse the second half using recursion and append the first half, that is the first node at the end of the reversed linked list. Return the head of the reversed linked list.
 
Algorithm
 
• If the list contains only one node, return the head of the list.
• Else, divide the ...read more
Answered by CodingNinjas
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Round duration - 30 minutes
Round difficulty - Hard

There was only one interviewer for this round. He continuously interacted with me and was giving me some good situational problems that were not very easy to answer. Basically those were open-minded questions which can be answered oth ways and that's why I found it quiet hard as per my nature but at the end things went well for me.

Q1. Basic Puzzles
A noticeable aspect in this puzzles is the fact that there’s a circular misplacement, which implies if apple is wrongly labelled as Apple, Apple can’t be labelled as Orange, i.e., it has to be...read more
Ans. 
Note: basically it's better if you have seen some puzzles before any HR round since they will give you an idea of what kind of problem you may encounter and then you can ace any difficult to difficult HR interview.
Answered by CodingNinjas
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