DSA INTERVIEW QUESTIONS AND ANSWERS

1. What is the difference between file structure and storage structure?
The difference lies in the memory area accessed. Storage structure refers to the data structure in the memory of the computer system,
whereas file structure represents the storage structure in the auxiliary memory.

2. Are linked lists considered linear or non-linear Data Structures?
Linked lists are considered both linear and non-linear data structures depending upon the application they are used for. When used for
access strategies, it is considered as a linear data-structure. When used for data storage, it is considered a non-linear data structure.

3. How do you reference all of the elements in a one-dimension array?
All of the elements in a one-dimension array can be referenced using an indexed loop as the array subscript so that the counter runs
from 0 to the array size minus one.

4. What are dynamic Data Structures? Name a few.
They are collections of data in memory that expand and contract to grow or shrink in size as a program runs. This enables the programmer
to control exactly how much memory is to be utilized.Examples are the dynamic array, linked list, stack, queue, and heap.

5. What is a Dequeue?
It is a double-ended queue, or a data structure, where the elements can be inserted or deleted at both ends (FRONT and REAR).

6. What operations can be performed on queues?
enqueue() adds an element to the end of the queue
dequeue() removes an element from the front of the queue
init() is used for initializing the queue
isEmpty tests for whether or not the queue is empty
The front is used to get the value of the first data item but does not remove it
The rear is used to get the last item from a queue.

7. What is the merge sort? How does it work?
Merge sort is a divide-and-conquer algorithm for sorting the data. It works by merging and sorting adjacent data to create bigger sorted
lists, which are then merged recursively to form even bigger sorted lists until you have one single sorted list.

8.How does the Selection sort work?
Selection sort works by repeatedly picking the smallest number in ascending order from the list and placing it at the beginning. This process is repeated moving toward the end of the list or sorted subarray.

Scan all items and find the smallest. Switch over the position as the first item. Repeat the selection sort on the remaining N-1 items. We always iterate forward (i from 0 to N-1) and swap with the smallest element (always i).

Time complexity: best case O(n2); worst O(n2)

Space complexity: worst O(1)

9. What are the applications of graph Data Structure?
Transport grids where stations are represented as vertices and routes as the edges of the graph
Utility graphs of power or water, where vertices are connection points and edge the wires or pipes connecting them
Social network graphs to determine the flow of information and hotspots (edges and vertices)
Neural networks where vertices represent neurons and edge the synapses between them

10. What is an AVL tree?
An AVL (Adelson, Velskii, and Landi) tree is a height balancing binary search tree in which the difference of heights of the left
and right subtrees of any node is less than or equal to one. This controls the height of the binary search tree by not letting
it get skewed. This is used when working with a large data set, with continual pruning through insertion and deletion of data.

11. Differentiate NULL and VOID ?
Null is a value, whereas Void is a data type identifier
Null indicates an empty value for a variable, whereas void indicates pointers that have no initial size
Null means it never existed; Void means it existed but is not in effect

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🏆 – Java Developer

Stage 1 – Java Basics (Syntax, Data Types, Variables)
Stage 2 – Object-Oriented Programming (OOP)
Stage 3 – Exception Handling
Stage 4 – Java Collections Framework
Stage 5 – File I/O
Stage 6 – Multithreading and Concurrency
Stage 7 – Java Streams and Lambda Expressions
Stage 8 – JDBC
Stage 9 – Servlets and JSP
Stage 10 – Spring Framework Basics
Stage 11 – Spring Boot
Stage 12 – RESTful APIs with Spring
Stage 13 – Testing
Stage 14 – Deployment
Stage 15 – Build projects

Famous programming languages and their frameworks


1. Python:

    Frameworks:
        Django
        Flask
        Pyramid
        Tornado

2. JavaScript:

    Frameworks (Front-End):
        React
        Angular
        Vue.js
        Ember.js
    Frameworks (Back-End):
        Node.js (Runtime)
        Express.js
        Nest.js
        Meteor

3. Java:

    Frameworks:
        Spring Framework
        Hibernate
        Apache Struts
        Play Framework

4. Ruby:

    Frameworks:
        Ruby on Rails (Rails)
        Sinatra
        Hanami

5. PHP:

    Frameworks:
        Laravel
        Symfony
        CodeIgniter
        Yii
        Zend Framework

6. C#:

    Frameworks:
        .NET Framework
        ASP.NET
        ASP.NET Core

7. Go (Golang):

    Frameworks:
        Gin
        Echo
        Revel

8. Rust:

    Frameworks:
        Rocket
        Actix
        Warp

9. Swift:

    Frameworks (iOS/macOS):
        SwiftUI
        UIKit
        Cocoa Touch

10. Kotlin:
- Frameworks (Android):
- Android Jetpack
- Ktor

11. TypeScript:
- Frameworks (Front-End):
- Angular
- Vue.js (with TypeScript)
- React (with TypeScript)

12. Scala:
- Frameworks:
- Play Framework
- Akka

13. Perl:
- Frameworks:
- Dancer
- Catalyst

14. Lua:
- Frameworks:
- OpenResty (for web development)

15. Dart:
- Frameworks:
- Flutter (for mobile app development)

16. R:
- Frameworks (for data science and statistics):
- Shiny
- ggplot2

17. Julia:
- Frameworks (for scientific computing):
- Pluto.jl
- Genie.jl

18. MATLAB:
- Frameworks (for scientific and engineering applications):
- Simulink

19. COBOL:
- Frameworks:
- COBOL-IT

20. Erlang:
- Frameworks:
- Phoenix (for web applications)

21. Groovy:
- Frameworks:
- Grails (for web applications)

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The reason you're not feeling motivated is because you don't have a clear goal.

You do have a goal, but it's only that you want to make a lot of money. With just that, you'll only experience FOMO (fear of missing out), not money.

Hard work is your responsibility, but you need to set small and immediate goals. For example, if you're studying DSA, it's not something you can complete in one day. A goal for now should be to master one topic thoroughly until you can solve all medium-level questions, and slowly, you'll crack it.

This is crucial at every stage of life.

Motivation will come when you start achieving small things, and eventually, everything will fall into place one day. ♥️

If you aspire to work in top product companies, here’s my advice:

👉 For SDE-1 or SWE positions, focus on:

✔️ Continuously upskilling and improving your abilities.
✔️ Developing strong problem-solving skills.
✔️Mastering DSA – trust me, you’ll be tested on it, so aim to excel.

Also, learn how to design scalable systems and understand how to build solutions that can handle growth in users and data.

👉 For higher-level roles (SDE-2 and SDE-3), focus on:

✔️ DSA + System Design (both LLD and HLD).
✔️ Building your leadership skills, as you’ll need to lead teams and projects.

🔸I know it’s challenging to do this while working full-time, but you’ll need to carve out time to consistently upskill yourself.

Remember, your learning plan should be sensible and well-organized.

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ENJOY LEARNING 👍👍

Python Data Types Cheat Sheet

R Programming for data analysis
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C Programming documentation from Microsoft

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Are you part of Rat Race?

A student who got 3.8 CGPA is unhappy because another student got 4 CGPA.

The student with 4 CGPA is unhappy because he/she is not placed in a Core Company.

Student placed in a Core Company is unhappy because his colleague has more salary than him/her.

The person having the highest salary in a company is unhappy because he/she has no time at all to enjoy their life with friends and family.

This is what happens when you get trapped in the infinite rat race. You are never happy. And you will never appreciate or be grateful for the life you have.

Come out of the Rat Race.

Art by: Steve Cutts