Learning DSA wasn’t just about acing interviews, --- it was about thinking better, building faster, and debugging smarter.

🎯 𝗛𝗲𝗿𝗲 𝗮𝗿𝗲 𝘁𝗵𝗲 𝟵 𝗰𝗼𝗿𝗲 𝗽𝗮𝘁𝘁𝗲𝗿𝗻𝘀 𝘁𝗵𝗮𝘁 𝘁𝗿𝗮𝗻𝘀𝗳𝗼𝗿𝗺𝗲𝗱 𝗵𝗼𝘄 𝗜 𝘀𝗼𝗹𝘃𝗲 𝗽𝗿𝗼𝗯𝗹𝗲𝗺𝘀:
• Sliding Windows
• Two Pointers
• Stack Based Patterns
• Dynamic Programing
• BFS/DFS (Trees & Graphs)
• Merge Intervals
• Backtracking & Subsets
• top-k Elements (Heaps)
• Greedy Techniques


🛤️ 𝗠𝘆 𝗣𝗮𝘁𝗵 𝘁𝗼 𝗠𝗮𝘀𝘁𝗲𝗿𝗶𝗻𝗴 𝗗𝗦𝗔:
• Started with basic problems on arrays & strings
• Solved 1-2 problems a day, consistently for 3 months
• Focused more on patterns than individual questions
• Made my own notes, revisited problems I struggled with
• Used visual tools to understand recursion & DP
• Practiced explaining my solutions out loud (like system design reviews)
• Applied patterns in real-world projects (DevOps automation, log parsing, infra tools)


💡 𝗟𝗼𝗼𝗸𝗶𝗻𝗴 𝗯𝗮𝗰𝗸, 𝗼𝗻𝗲 𝘁𝗵𝗶𝗻𝗴 𝗶𝘀 𝗰𝗹𝗲𝗮𝗿:
> It's not how many problems you solve, it's how well you can recognize the pattern hiding in each one.

You can find more free resources on my WhatsApp channel: https://whatsapp.com/channel/0029VahiFZQ4o7qN54LTzB17

A-Z in Programming ✅

Theoretical Questions for Coding Interviews on Basic Data Structures

1. What is a Data Structure?
A data structure is a way of organizing and storing data so that it can be accessed and modified efficiently. Common data structures include arrays, linked lists, stacks, queues, and trees.

2. What is an Array?
An array is a collection of elements, each identified by an index. It has a fixed size and stores elements of the same type in contiguous memory locations.

3. What is a Linked List?
A linked list is a linear data structure where elements (nodes) are stored non-contiguously. Each node contains a value and a reference (or link) to the next node. Unlike arrays, linked lists can grow dynamically.

4. What is a Stack?
A stack is a linear data structure that follows the Last In, First Out (LIFO) principle. The most recently added element is the first one to be removed. Common operations include push (add an element) and pop (remove an element).

5. What is a Queue?
A queue is a linear data structure that follows the First In, First Out (FIFO) principle. The first element added is the first one to be removed. Common operations include enqueue (add an element) and dequeue (remove an element).

6. What is a Binary Tree?
A binary tree is a hierarchical data structure where each node has at most two children, usually referred to as the left and right child. It is used for efficient searching and sorting.

7. What is the difference between an array and a linked list?

Array: Fixed size, elements stored in contiguous memory.

Linked List: Dynamic size, elements stored non-contiguously, each node points to the next.


8. What is the time complexity for accessing an element in an array vs. a linked list?

Array: O(1) for direct access by index.

Linked List: O(n) for access, as you must traverse the list from the start to find an element.


9. What is the time complexity for inserting or deleting an element in an array vs. a linked list?

Array:

Insertion/Deletion at the end: O(1).

Insertion/Deletion at the beginning or middle: O(n) because elements must be shifted.


Linked List:

Insertion/Deletion at the beginning: O(1).

Insertion/Deletion in the middle or end: O(n), as you need to traverse the list.



10. What is a HashMap (or Dictionary)?
A HashMap is a data structure that stores key-value pairs. It allows efficient lookups, insertions, and deletions using a hash function to map keys to values. Average time complexity for these operations is O(1).

Coding interview: https://whatsapp.com/channel/0029VammZijATRSlLxywEC3X

Essential Python Libraries for Data Science

- Numpy: Fundamental for numerical operations, handling arrays, and mathematical functions.

- SciPy: Complements Numpy with additional functionalities for scientific computing, including optimization and signal processing.

- Pandas: Essential for data manipulation and analysis, offering powerful data structures like DataFrames.

- Matplotlib: A versatile plotting library for creating static, interactive, and animated visualizations.

- Keras: A high-level neural networks API, facilitating rapid prototyping and experimentation in deep learning.

- TensorFlow: An open-source machine learning framework widely used for building and training deep learning models.

- Scikit-learn: Provides simple and efficient tools for data mining, machine learning, and statistical modeling.

- Seaborn: Built on Matplotlib, Seaborn enhances data visualization with a high-level interface for drawing attractive and informative statistical graphics.

- Statsmodels: Focuses on estimating and testing statistical models, providing tools for exploring data, estimating models, and statistical testing.

- NLTK (Natural Language Toolkit): A library for working with human language data, supporting tasks like classification, tokenization, stemming, tagging, parsing, and more.

These libraries collectively empower data scientists to handle various tasks, from data preprocessing to advanced machine learning implementations.

ENJOY LEARNING 👍👍

8 Essential GitHub Repositories for developers 🚀👇

1. The Developer Roadmap by Kamran Ahmed 👇
https://github.com/kamranahmedse/developer-roadmap

2. Every Programmer Should Know by MTDVIO 👇
https://github.com/mtdvio/every-programmer-should-know

3. Awesome Algorithms by Taylan Pince 👇
https://github.com/tayllan/awesome-algorithms

4. DSA Bootcamp Java by Kunal Kushwaha 👇
https://github.com/kunal-kushwaha/DSA-Bootcamp-Java

5. WTFJS by Denys Dovhan 👇
https://github.com/denysdovhan/wtfjs

6. Frontend Developer Interview Questions by h5bp 👇
https://github.com/h5bp/Front-end-Developer-Interview-Questions

7. ReactJS Interview Questions & Answers by Sudheer Jonna 👇
https://github.com/sudheerj/reactjs-interview-questions

8. Awesome Cheatsheets by Alain Couprie 👇
https://github.com/LeCoupa/awesome-cheatsheets

𝗣𝗮𝘆 𝗔𝗳𝘁𝗲𝗿 𝗣𝗹𝗮𝗰𝗲𝗺𝗲𝗻𝘁 𝗧𝗿𝗮𝗶𝗻𝗶𝗻𝗴 😍

𝗟𝗲𝗮𝗿𝗻 𝗖𝗼𝗱𝗶𝗻𝗴 & 𝗚𝗲𝘁 𝗣𝗹𝗮𝗰𝗲𝗱 𝗜𝗻 𝗧𝗼𝗽 𝗠𝗡𝗖𝘀

 Eligibility:- BE/BTech / BCA / BSc

🌟 2000+ Students Placed
🤝 500+ Hiring Partners
💼 Avg. Rs. 7.4 LPA
🚀 41 LPA Highest Package

𝗕𝗼𝗼𝗸 𝗮 𝗙𝗥𝗘𝗘 𝗗𝗲𝗺𝗼👇:-

𝗢𝗻𝗹𝗶𝗻𝗲 :- https://pdlink.in/4hO7rWY

🔹 Hyderabad :- https://pdlink.in/4cJUWtx

🔹 Pune :- https://pdlink.in/3YA32zi

🔹 Noida :- https://linkpd.in/NoidaFSD

( Hurry Up 🏃‍♂️Limited Slots )

One day or Day one. You decide.

Data Science edition.

𝗢𝗻𝗲 𝗗𝗮𝘆 : I will learn SQL.
𝗗𝗮𝘆 𝗢𝗻𝗲: Download mySQL Workbench.

𝗢𝗻𝗲 𝗗𝗮𝘆: I will build my projects for my portfolio.
𝗗𝗮𝘆 𝗢𝗻𝗲: Look on Kaggle for a dataset to work on.

𝗢𝗻𝗲 𝗗𝗮𝘆: I will master statistics.
𝗗𝗮𝘆 𝗢𝗻𝗲: Start the free Khan Academy Statistics and Probability course.

𝗢𝗻𝗲 𝗗𝗮𝘆: I will learn to tell stories with data.
𝗗𝗮𝘆 𝗢𝗻𝗲: Install Tableau Public and create my first chart.

𝗢𝗻𝗲 𝗗𝗮𝘆: I will become a Data Scientist.
𝗗𝗮𝘆 𝗢𝗻𝗲: Update my resume and apply to some Data Science job postings.

📊𝗗𝗮𝘁𝗮 𝗔𝗻𝗮𝗹𝘆𝘁𝗶𝗰𝘀 𝗙𝗥𝗘𝗘 𝗖𝗲𝗿𝘁𝗶𝗳𝗶𝗰𝗮𝘁𝗶𝗼𝗻 𝗖𝗼𝘂𝗿𝘀𝗲𝘀 - 𝟭𝟬𝟬% 𝗙𝗥𝗘𝗘 😍

Start learning industry-relevant data skills today at zero cost!

✅ 100% FREE Certification
✅ Learn Data Analysis, Excel, SQL, Power BI & more
✅ Boost your resume with job-ready skills

🚀 Perfect for Students, Freshers & Career Switchers

𝐋𝐢𝐧𝐤 👇:- 
 
https://pdlink.in/4lp7hXQ
 
🎓 Enroll Now & Get Certified

Advanced programming concepts you should know 👇👇

✅ 1. Object-Oriented Programming (OOP)
Think of it like real life: A car is an object with properties (color, speed) and methods (drive, brake). You build code using reusable objects.

✅ 2. Inheritance
Like family traits: A child class gets features from a parent class.
Example: A Dog class can inherit from an Animal class.

✅ 3. Polymorphism
One thing, many forms.
Like a button that does different things depending on the app. Same action, different results.

✅ 4. Encapsulation
Hiding details to keep it clean.
Like using a microwave—you press a button, don’t worry about how it works inside.

✅ 5. Recursion
When a function calls itself.
Like Russian dolls inside each other. Useful for problems like solving a maze or calculating factorials.

✅ 6. Asynchronous Programming
Doing many things at once.
Like cooking while waiting for a download. It avoids “blocking” other tasks.

✅ 7. APIs
Like a waiter between your code and a service.
You say, “Get me the weather,” the API brings the data for you.

✅ 8. Data Structures & Algorithms
Data structures = ways to organize info (like shelves).
Algorithms = steps to solve a problem (like a recipe).

✅ 9. Big-O Notation
A way to measure how fast or slow your code runs as data grows.
More efficient code = faster apps!

✅ 10. Design Patterns
Reusable solutions to common coding problems.
Like blueprints for building a house, but for code.

React ♥️ for more

𝟯 𝗙𝗥𝗘𝗘 𝗖𝗲𝗿𝘁𝗶𝗳𝗶𝗰𝗮𝘁𝗶𝗼𝗻𝘀 𝗧𝗼 𝗠𝗮𝘀𝘁𝗲𝗿 𝗜𝗻 𝟮𝟬𝟮𝟱😍

Upgrade your skills without spending a penny!

1️⃣ AI & ML –  https://pdlink.in/3U3eZuq

2️⃣ Data Analytics –  https://pdlink.in/4lp7hXQ

3️⃣ Microsoft & AWS  – https://pdlink.in/4m3FwTX

🎯 Learn Online | High Value | Certificates Included ✅

SQL Interview Questions for 0-1 year of Experience (Asked in Top Product-Based Companies).

Sharpen your SQL skills with these real interview questions!

Q1. Customer Purchase Patterns -
You have two tables, Customers and Purchases: CREATE TABLE Customers ( customer_id INT PRIMARY KEY, customer_name VARCHAR(255) ); CREATE TABLE Purchases ( purchase_id INT PRIMARY KEY, customer_id INT, product_id INT, purchase_date DATE );
Assume necessary INSERT statements are already executed.
Write an SQL query to find the names of customers who have purchased more than 5 different products within the last month. Order the result by customer_name.

Q2. Call Log Analysis -
Suppose you have a CallLogs table: CREATE TABLE CallLogs ( log_id INT PRIMARY KEY, caller_id INT, receiver_id INT, call_start_time TIMESTAMP, call_end_time TIMESTAMP );
Assume necessary INSERT statements are already executed.
Write a query to find the average call duration per user. Include only users who have made more than 10 calls in total. Order the result by average duration descending.

Q3. Employee Project Allocation - Consider two tables, Employees and Projects:
CREATE TABLE Employees ( employee_id INT PRIMARY KEY, employee_name VARCHAR(255), department VARCHAR(255) ); CREATE TABLE Projects ( project_id INT PRIMARY KEY, lead_employee_id INT, project_name VARCHAR(255), start_date DATE, end_date DATE );
Assume necessary INSERT statements are already executed.
The goal is to write an SQL query to find the names of employees who have led more than 3 projects in the last year. The result should be ordered by the number of projects led.