Coding Interview Resources
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This channel contains the free resources and solution of coding problems which are usually asked in the interviews.

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Here is a great JavaScript interview question!

What the heck is a Promise doing under the hood?

In JavaScript, things usually happen one after the other. It's like a checklist each item gets done before moving to the next.

When a function returns a Promise, it's like making a promise to do something, like fetch data from the internet. But JavaScript doesn't wait around for the data to come back. Instead, it moves on to the next task.

Now, here's where things get interesting. While JavaScript is busy doing other stuff, like running more code, the Promise is off fetching data in the background.

Once the data is fetched, the Promise is fulfilled, and it has some information to share. But JavaScript needs to know when it's time to handle that information. That's where the onFulfilled part of the Promise comes in.

When the Promise is fulfilled, JavaScript takes the onFulfilled code and puts it in a special queue, ready to be run.

Now, async/await enters the scene. When we mark a function as async, we're telling JavaScript, "Hey, this function might take some time to finish, so don't wait up for it."

And when we use the await keyword inside an async function, it's like saying, "Hold on a sec, JavaScript. I need to wait for something important before moving on."

So, when JavaScript encounters an await keyword, it pauses and lets the async function do its thing. If that thing happens to be a Promise, JavaScript knows it can move on to other tasks while waiting for the Promise to resolve.

Once the Promise is resolved, JavaScript picks up where it left off and continues running the code.

Promises and async/await allow JavaScript to handle asynchronous tasks while keeping things organized and in order. Promises handle the background tasks, while async/await makes it easier to work with them in our code, ensuring everything happens in the right sequence.

Web Development Best Resources: https://topmate.io/coding/930165

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Which programming language should I use on interview?

Companies usually let you choose, in which case you should use your most comfortable language. If you know a bunch of languages, prefer one that lets you express more with fewer characters and fewer lines of code, like Python or Ruby. It keeps your whiteboard cleaner.

Try to stick with the same language for the whole interview, but sometimes you might want to switch languages for a question. E.g., processing a file line by line will be far easier in Python than in C++.

Sometimes, though, your interviewer will do this thing where they have a pet question thatโ€™s, for example, C-specific. If you list C on your resume, theyโ€™ll ask it.

So keep that in mind! If youโ€™re not confident with a language, make that clear on your resume. Put your less-strong languages under a header like โ€˜Working Knowledge.โ€™
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Complete roadmap to learn Python and Data Structures & Algorithms (DSA) in 2 months

### Week 1: Introduction to Python

Day 1-2: Basics of Python
- Python setup (installation and IDE setup)
- Basic syntax, variables, and data types
- Operators and expressions

Day 3-4: Control Structures
- Conditional statements (if, elif, else)
- Loops (for, while)

Day 5-6: Functions and Modules
- Function definitions, parameters, and return values
- Built-in functions and importing modules

Day 7: Practice Day
- Solve basic problems on platforms like HackerRank or LeetCode

### Week 2: Advanced Python Concepts

Day 8-9: Data Structures in Python
- Lists, tuples, sets, and dictionaries
- List comprehensions and generator expressions

Day 10-11: Strings and File I/O
- String manipulation and methods
- Reading from and writing to files

Day 12-13: Object-Oriented Programming (OOP)
- Classes and objects
- Inheritance, polymorphism, encapsulation

Day 14: Practice Day
- Solve intermediate problems on coding platforms

### Week 3: Introduction to Data Structures

Day 15-16: Arrays and Linked Lists
- Understanding arrays and their operations
- Singly and doubly linked lists

Day 17-18: Stacks and Queues
- Implementation and applications of stacks
- Implementation and applications of queues

Day 19-20: Recursion
- Basics of recursion and solving problems using recursion
- Recursive vs iterative solutions

Day 21: Practice Day
- Solve problems related to arrays, linked lists, stacks, and queues

### Week 4: Fundamental Algorithms

Day 22-23: Sorting Algorithms
- Bubble sort, selection sort, insertion sort
- Merge sort and quicksort

Day 24-25: Searching Algorithms
- Linear search and binary search
- Applications and complexity analysis

Day 26-27: Hashing
- Hash tables and hash functions
- Collision resolution techniques

Day 28: Practice Day
- Solve problems on sorting, searching, and hashing

### Week 5: Advanced Data Structures

Day 29-30: Trees
- Binary trees, binary search trees (BST)
- Tree traversals (in-order, pre-order, post-order)

Day 31-32: Heaps and Priority Queues
- Understanding heaps (min-heap, max-heap)
- Implementing priority queues using heaps

Day 33-34: Graphs
- Representation of graphs (adjacency matrix, adjacency list)
- Depth-first search (DFS) and breadth-first search (BFS)

Day 35: Practice Day
- Solve problems on trees, heaps, and graphs

### Week 6: Advanced Algorithms

Day 36-37: Dynamic Programming
- Introduction to dynamic programming
- Solving common DP problems (e.g., Fibonacci, knapsack)

Day 38-39: Greedy Algorithms
- Understanding greedy strategy
- Solving problems using greedy algorithms

Day 40-41: Graph Algorithms
- Dijkstraโ€™s algorithm for shortest path
- Kruskalโ€™s and Primโ€™s algorithms for minimum spanning tree

Day 42: Practice Day
- Solve problems on dynamic programming, greedy algorithms, and advanced graph algorithms

### Week 7: Problem Solving and Optimization

Day 43-44: Problem-Solving Techniques
- Backtracking, bit manipulation, and combinatorial problems

Day 45-46: Practice Competitive Programming
- Participate in contests on platforms like Codeforces or CodeChef

Day 47-48: Mock Interviews and Coding Challenges
- Simulate technical interviews
- Focus on time management and optimization

Day 49: Review and Revise
- Go through notes and previously solved problems
- Identify weak areas and work on them

### Week 8: Final Stretch and Project

Day 50-52: Build a Project
- Use your knowledge to build a substantial project in Python involving DSA concepts

Day 53-54: Code Review and Testing
- Refactor your project code
- Write tests for your project

Day 55-56: Final Practice
- Solve problems from previous contests or new challenging problems

Day 57-58: Documentation and Presentation
- Document your project and prepare a presentation or a detailed report

Day 59-60: Reflection and Future Plan
- Reflect on what you've learned
- Plan your next steps (advanced topics, more projects, etc.)

Best DSA RESOURCES: https://topmate.io/coding/886874

Credits: https://t.me/free4unow_backup

ENJOY LEARNING ๐Ÿ‘๐Ÿ‘
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7 Most Popular Programming Languages in 2025

1. Python

The Jack of All Trades

Why it's loved: Simple syntax, huge community, beginner-friendly.

Used for: Data Science, Machine Learning, Web Development, Automation.

Who uses it: Data analysts, backend developers, researchers, even kids learning to code.


2. JavaScript

The Language of the Web

Why it's everywhere: Runs in every browser, now also on servers (Node.js).

Used for: Frontend & backend web apps, interactive UI, full-stack apps.

Who uses it: Web developers, app developers, UI/UX enthusiasts.


3. Java

The Enterprise Backbone

Why it stands strong: Portable, secure, scalable โ€” runs on everything from desktops to Android devices.

Used for: Android apps, enterprise software, backend systems.

Who uses it: Large corporations, Android developers, system architects.


4. C/C++

The Power Players

Why they matter: Super fast, close to the hardware, great for performance-critical apps.

Used for: Game engines, operating systems, embedded systems.

Who uses it: System programmers, game developers, performance-focused engineers.


5. C#

Microsoftโ€™s Darling

Why it's growing: Built into the .NET ecosystem, great for Windows apps and games.

Used for: Desktop applications, Unity game development, enterprise tools.

Who uses it: Game developers, enterprise app developers, Windows lovers.


6. SQL

The Language of Data

Why itโ€™s essential: Every application needs a database โ€” SQL helps you talk to it.

Used for: Querying databases, reporting, analytics.

Who uses it: Data analysts, backend devs, business intelligence professionals.


7. Go (Golang)

The Modern Minimalist

Why itโ€™s rising: Simple, fast, and built for scale โ€” ideal for cloud-native apps.

Used for: Web servers, microservices, distributed systems.

Who uses it: Backend engineers, DevOps, cloud developers.

Free Coding Resources: https://whatsapp.com/channel/0029VahiFZQ4o7qN54LTzB17
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Perfect ๐Ÿ˜‚
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Java coding interview questions

1. Reverse a String:
Write a Java program to reverse a given string.
2. Find the Largest Element in an Array:
Find and print the largest element in an array.
3. Check for Palindrome:
Determine if a given string is a palindrome (reads the same backward as forward).
4. Factorial Calculation:
Write a function to calculate the factorial of a number.
5. Fibonacci Series:
Generate the first n numbers in the Fibonacci sequence.
6. Check for Prime Number:
Write a program to check if a given number is prime.
7. String Anagrams:
Determine if two strings are anagrams of each other.

8. Array Sorting:
Implement sorting algorithms like bubble sort, merge sort, or quicksort.

9. Binary Search:
Implement a binary search algorithm to find an element in a sorted array.

10. Duplicate Elements in an Array:
Find and print duplicate elements in an array.

11. Linked List Reversal:
Reverse a singly-linked list.

12. Matrix Operations:
Perform matrix operations like addition, multiplication, or transpose.

13. Implement a Stack:
Create a stack data structure and implement basic operations (push, pop).

14. Implement a Queue:
Create a queue data structure and implement basic operations (enqueue, dequeue).

15. Inheritance and Polymorphism:
Implement a class hierarchy with inheritance and demonstrate polymorphism.

16. Exception Handling:
Write code that demonstrates the use of try-catch blocks to handle exceptions.
17. File I/O:
Read from and write to a file using Java's file I/O capabilities.
18. Multithreading:
Create a simple multithreaded program and demonstrate thread synchronization.
19. Lambda Expressions:
Use lambda expressions to implement functional interfaces.
20. Recursive Algorithms:
Solve a problem using recursion, such as computing the factorial or Fibonacci sequence.

Best Java Resources: https://whatsapp.com/channel/0029VamdH5mHAdNMHMSBwg1s

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Python For Finance
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๐Ÿ’ป Want to Clear Your Next Java Developer Interview?

Prepare these topics to ace your next Java interview! ๐Ÿš€

๐“๐จ๐ฉ๐ข๐œ ๐Ÿ: ๐๐ซ๐จ๐ฃ๐ž๐œ๐ญ ๐…๐ฅ๐จ๐ฐ ๐š๐ง๐ ๐€๐ซ๐œ๐ก๐ข๐ญ๐ž๐œ๐ญ๐ฎ๐ซ๐ž
๐Ÿ”น Describe your project and its architecture.
๐Ÿ”น Challenges faced and your role in the project.
๐Ÿ”น Tech stack used and the reasoning behind it.
๐Ÿ”น Problem-solving, collaboration, and lessons learned.
๐Ÿ”น Reflect on what you'd do differently.

๐“๐จ๐ฉ๐ข๐œ ๐Ÿ: ๐‚๐จ๐ซ๐ž ๐‰๐š๐ฏ๐š
๐Ÿ”น String concepts (hashcode, equals).
๐Ÿ”น Immutability, OOPS concepts.
๐Ÿ”น Serialization, Collection Framework.
๐Ÿ”น Exception handling, multithreading.
๐Ÿ”น Java Memory Model, garbage collection.

๐“๐จ๐ฉ๐ข๐œ ๐Ÿ‘: ๐‰๐š๐ฏ๐š ๐Ÿ–/๐Ÿ๐Ÿ/๐Ÿ๐Ÿ• Features
๐Ÿ”น Java 8 features: Lambda expressions, Stream API, Optional API.
๐Ÿ”น Functional interfaces, default/static methods.
๐Ÿ”น Pattern matching, text blocks, modules.

๐“๐จ๐ฉ๐ข๐œ ๐Ÿ’: ๐’๐ฉ๐ซ๐ข๐ง๐  & ๐’๐ฉ๐ซ๐ข๐ง๐  ๐๐จ๐จ๐ญ
๐Ÿ”น Dependency Injection, IOC, Spring MVC.
๐Ÿ”น Bean lifecycle, scopes, profiles.
๐Ÿ”น REST API, CRUD, AOP, Exception handling.
๐Ÿ”น JWT, OAuth, actuators, WebFlux.
๐Ÿ”น Microservices, Spring Cloud, JPA.

๐“๐จ๐ฉ๐ข๐œ ๐Ÿ“: ๐ƒ๐š๐ญ๐š๐›๐š๐ฌ๐ž (๐’๐๐‹/๐๐จ๐’๐๐‹)
๐Ÿ”น JPA repositories, entity relationships.
๐Ÿ”น SQL queries (e.g., Nth highest salary).
๐Ÿ”น Relational and non-relational DB concepts.
๐Ÿ”น Joins, indexing, stored procedures.

๐“๐จ๐ฉ๐ข๐œ ๐Ÿ”: ๐‚๐จ๐๐ข๐ง๐ 
๐Ÿ”น DSA-based questions.
๐Ÿ”น Sorting/searching with Java APIs.
๐Ÿ”น Stream API coding questions.

๐“๐จ๐ฉ๐ข๐œ ๐Ÿ•: ๐ƒ๐ž๐ฏ๐Ž๐ฉ๐ฌ & ๐ƒ๐ž๐ฉ๐ฅ๐จ๐ฒ๐ฆ๐ž๐ง๐ญ
๐Ÿ”น Familiarize yourself with tools like Jenkins, Kubernetes, Kafka, and cloud technologies.

๐“๐จ๐ฉ๐ข๐œ ๐Ÿ–: ๐๐ž๐ฌ๐ญ ๐๐ซ๐š๐œ๐ญ๐ข๐œ๐ž๐ฌ
๐Ÿ”น Master design patterns like singleton, factory, observer, etc.

โœจ Nail your interview with confidence! โœจ

#JavaInterview #JavaDeveloper
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Complete Syllabus for Data Analytics interview:

SQL:
1. Basic   
- SELECT statements with WHERE, ORDER BY, GROUP BY, HAVING   
- Basic JOINS (INNER, LEFT, RIGHT, FULL)   
- Creating and using simple databases and tables

2. Intermediate   
- Aggregate functions (COUNT, SUM, AVG, MAX, MIN)   
- Subqueries and nested queries
- Common Table Expressions (WITH clause)   
- CASE statements for conditional logic in queries
3. Advanced   
- Advanced JOIN techniques (self-join, non-equi join)   
- Window functions (OVER, PARTITION BY, ROW_NUMBER, RANK, DENSE_RANK, lead, lag)   
- optimization with indexing   
- Data manipulation (INSERT, UPDATE, DELETE)

Python:
1. Basic   
- Syntax, variables, data types (integers, floats, strings, booleans)   
- Control structures (if-else, for and while loops)   
- Basic data structures (lists, dictionaries, sets, tuples)   
- Functions, lambda functions, error handling (try-except)   
- Modules and packages

2. Pandas & Numpy   
- Creating and manipulating DataFrames and Series   
- Indexing, selecting, and filtering data   
- Handling missing data (fillna, dropna)   
- Data aggregation with groupby, summarizing data   
- Merging, joining, and concatenating datasets

3. Basic Visualization   
- Basic plotting with Matplotlib (line plots, bar plots, histograms)   
- Visualization with Seaborn (scatter plots, box plots, pair plots)   
- Customizing plots (sizes, labels, legends, color palettes)   
- Introduction to interactive visualizations (e.g., Plotly)

Excel:
1. Basic   
- Cell operations, basic formulas (SUMIFS, COUNTIFS, AVERAGEIFS, IF, AND, OR, NOT & Nested Functions etc.)   
- Introduction to charts and basic data visualization   
- Data sorting and filtering   
- Conditional formatting

2. Intermediate   
- Advanced formulas (V/XLOOKUP, INDEX-MATCH, nested IF)   
- PivotTables and PivotCharts for summarizing data   
- Data validation tools   
- What-if analysis tools (Data Tables, Goal Seek)

3. Advanced   
- Array formulas and advanced functions   
- Data Model & Power Pivot
- Advanced Filter
- Slicers and Timelines in Pivot Tables   
- Dynamic charts and interactive dashboards

Power BI:
1. Data Modeling   
- Importing data from various sources   
- Creating and managing relationships between different datasets   
- Data modeling basics (star schema, snowflake schema)

2. Data Transformation   
- Using Power Query for data cleaning and transformation   
- Advanced data shaping techniques   
- Calculated columns and measures using DAX

3. Data Visualization and Reporting   - Creating interactive reports and dashboards   
- Visualizations (bar, line, pie charts, maps)   
- Publishing and sharing reports, scheduling data refreshes

Statistics Fundamentals: Mean, Median, Mode, Standard Deviation, Variance, Probability Distributions, Hypothesis Testing, P-values, Confidence Intervals, Correlation, Simple Linear Regression, Normal Distribution, Binomial Distribution, Poisson Distribution.

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Java for Everything: โ˜•

Java + Spring = Enterprise Applications

Java + Hibernate = Object-Relational Mapping

Java + Android = Mobile App Development

Java + Swing = Desktop GUI Applications

Java + JavaFX = Modern GUI Applications

Java + JUnit = Unit Testing

Java + Maven = Project Management

Java + Jenkins = Continuous Integration

Java + Apache Kafka = Stream Processing

Java + Apache Hadoop = Big Data Processing

Java + Microservices = Scalable Services

Best Programming Resources: https://topmate.io/coding/886839

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Data Structure Cheat Sheet
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Here are 20 essential VS Code shortcuts for beginners:

1. Ctrl + P: Open any file quickly ๐Ÿ“‚

2. Ctrl + /: Toggle line comment ๐Ÿ“

3. Alt + Up/Down: Move a line up or down โ†•๏ธ

4. Ctrl + Shift + K: Delete the current line โŒ

5. Ctrl + B: Show/hide the sidebar ๐Ÿ“š

6. Ctrl + Space: Trigger IntelliSense for code suggestions ๐Ÿ’ก

7. Ctrl + Shift + F: Search across files ๐Ÿ”

8. Ctrl + D: Select the next occurrence of the selected text ๐Ÿ“‘

9. Ctrl + Shift + L: Select all occurrences of the current selection ๐Ÿ”—

10. Ctrl + Shift + P: Open the Command Palette ๐Ÿ“œ

11. Ctrl + F2: Rename all occurrences of a variable โœ๏ธ

12. Ctrl + J: Show/hide the integrated terminal ๐Ÿ’ป

13. Ctrl + `: Open a new terminal ๐Ÿ”ง

14. Ctrl + Shift + N: Open a new window ๐Ÿ–ผ๏ธ

15. Ctrl + W: Close the current editor tab ๐Ÿ—‚๏ธ

16. Ctrl + Shift + E: Focus on the file explorer ๐Ÿ—ƒ๏ธ

17. Ctrl + Shift + G: Open the Git view ๐Ÿ”„

18. Ctrl + Shift + M: Open the Problems panel ๐Ÿšจ

19. Alt + Shift + Up/Down: Copy the line up or down ๐Ÿ“‹

20. Ctrl + Alt + Arrow keys: Split the editor window โœ‚๏ธ


Master these and level up your coding speed! ๐Ÿš€
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๐Ÿ–ฅ VS Code Themes You Should Try
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