DSA (Data Structures and Algorithms) Essential Topics for Interviews
1️⃣ Arrays and Strings
Basic operations (insert, delete, update)
Two-pointer technique
Sliding window
Prefix sum
Kadane’s algorithm
Subarray problems
2️⃣ Linked List
Singly & Doubly Linked List
Reverse a linked list
Detect loop (Floyd’s Cycle)
Merge two sorted lists
Intersection of linked lists
3️⃣ Stack & Queue
Stack using array or linked list
Queue and Circular Queue
Monotonic Stack/Queue
LRU Cache (LinkedHashMap/Deque)
Infix to Postfix conversion
4️⃣ Hashing
HashMap, HashSet
Frequency counting
Two Sum problem
Group Anagrams
Longest Consecutive Sequence
5️⃣ Recursion & Backtracking
Base cases and recursive calls
Subsets, permutations
N-Queens problem
Sudoku solver
Word search
6️⃣ Trees & Binary Trees
Traversals (Inorder, Preorder, Postorder)
Height and Diameter
Balanced Binary Tree
Lowest Common Ancestor (LCA)
Serialize & Deserialize Tree
7️⃣ Binary Search Trees (BST)
Search, Insert, Delete
Validate BST
Kth smallest/largest element
Convert BST to DLL
8️⃣ Heaps & Priority Queues
Min Heap / Max Heap
Heapify
Top K elements
Merge K sorted lists
Median in a stream
9️⃣ Graphs
Representations (adjacency list/matrix)
DFS, BFS
Cycle detection (directed & undirected)
Topological Sort
Dijkstra’s & Bellman-Ford algorithm
Union-Find (Disjoint Set)
10️⃣ Dynamic Programming (DP)
0/1 Knapsack
Longest Common Subsequence
Matrix Chain Multiplication
DP on subsequences
Memoization vs Tabulation
11️⃣ Greedy Algorithms
Activity selection
Huffman coding
Fractional knapsack
Job scheduling
12️⃣ Tries
Insert and search a word
Word search
Auto-complete feature
13️⃣ Bit Manipulation
XOR, AND, OR basics
Check if power of 2
Single Number problem
Count set bits
Coding Interview Resources: https://whatsapp.com/channel/0029VammZijATRSlLxywEC3X
ENJOY LEARNING 👍👍
1️⃣ Arrays and Strings
Basic operations (insert, delete, update)
Two-pointer technique
Sliding window
Prefix sum
Kadane’s algorithm
Subarray problems
2️⃣ Linked List
Singly & Doubly Linked List
Reverse a linked list
Detect loop (Floyd’s Cycle)
Merge two sorted lists
Intersection of linked lists
3️⃣ Stack & Queue
Stack using array or linked list
Queue and Circular Queue
Monotonic Stack/Queue
LRU Cache (LinkedHashMap/Deque)
Infix to Postfix conversion
4️⃣ Hashing
HashMap, HashSet
Frequency counting
Two Sum problem
Group Anagrams
Longest Consecutive Sequence
5️⃣ Recursion & Backtracking
Base cases and recursive calls
Subsets, permutations
N-Queens problem
Sudoku solver
Word search
6️⃣ Trees & Binary Trees
Traversals (Inorder, Preorder, Postorder)
Height and Diameter
Balanced Binary Tree
Lowest Common Ancestor (LCA)
Serialize & Deserialize Tree
7️⃣ Binary Search Trees (BST)
Search, Insert, Delete
Validate BST
Kth smallest/largest element
Convert BST to DLL
8️⃣ Heaps & Priority Queues
Min Heap / Max Heap
Heapify
Top K elements
Merge K sorted lists
Median in a stream
9️⃣ Graphs
Representations (adjacency list/matrix)
DFS, BFS
Cycle detection (directed & undirected)
Topological Sort
Dijkstra’s & Bellman-Ford algorithm
Union-Find (Disjoint Set)
10️⃣ Dynamic Programming (DP)
0/1 Knapsack
Longest Common Subsequence
Matrix Chain Multiplication
DP on subsequences
Memoization vs Tabulation
11️⃣ Greedy Algorithms
Activity selection
Huffman coding
Fractional knapsack
Job scheduling
12️⃣ Tries
Insert and search a word
Word search
Auto-complete feature
13️⃣ Bit Manipulation
XOR, AND, OR basics
Check if power of 2
Single Number problem
Count set bits
Coding Interview Resources: https://whatsapp.com/channel/0029VammZijATRSlLxywEC3X
ENJOY LEARNING 👍👍
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Evolution of Programming Languages 🖥️
🔰Programming Languages🔰
1. JAVA:
More than 85% android apps are created using JAVA. It is also used in big (big means big) websites. It is a portable programming language which makes it easy to use on multi platforms.
2. Java Script:
Its a browser/client side language. It makes the webpage more interactive. Like for example when you enter a comment on Facebook then the whole page doesn’t load., just that comment is added. This kind of functionalities are added into webpages with JavaScript. Javascript brought about a revolution in webapps.
3. Assembly Language:
The most low level programming language because its nothing more than machine code written in human readable form. Its hard to write and you need to have deep understanding of computers to use this because you are really talking with it. Its very fast in terms of execution.
4. C:
Its a low level language too that’s why its fast. It is used to program operating system, computer games and software which need to be fast. It is hard to write but gives you more control of your computer.
5. C++ :
Its C with more features and those features make it more complex.
6. Perl:
A language which was developed to create small scripts easily . Programming in Perl is easy and efficient but the programs are comparatively slower.
7. Python:
Perl was made better and named Python. Its easy, efficient and flexible. You can automate things with python in a go.
8. Ruby:
Its similar to Python but it became popular when they created a web application development framework named Rails which lets developers to write their web application conveniently.
9. HTML and CSS:
HTML and CSS are languages not programming languages because they are just used display things on a website. They do not do any actual processing. HTML is used to create the basic structure of the website and then CSS is used to make it look good.
10. PHP:
It is used to process things in a website. It is server-sided language as it doesn’t get executed in user browser, but on the server. It can be used to generate dynamic webpage content.
11. SQL:
This is not exactly a programming language. It is used to interact with databases.
➡️ This list could be long because there are too many programming language but I introduced you to the popular ones.
❓Which Language Should Be Your First Programming Language?
✅ Suggestions..
1. Getting Started
Learn HTML & CSS. They are easy and will give you a basic idea of how programming works. You will be able to create your own webpages. After HTML you can go with PHP and SQL, so will have a good grasp over web designing and then you can go with python, C or Java. I assure you that PHP, HTML and SQL will be definitely useful in your hacking journey.
2. Understanding Computer And Programming Better
C..The classic C! C is one of the most foundational languages. If you learn C, you will have a deep knowledge of Computers and you will have a greater understanding of programming too, that will make you a better programmer. You will spend most of your time compiling though (just trying to crack a joke).
3. Too Eager To Create Programs?
Python! Python is very easy to learn and you can create a program which does something instead of programming calculators. Well Python doesn’t start you from the basics but with if you know python, you will be able to understand other languages better. One benefit of python is that you don’t need to compile the script to run it, just write one and run it.
React ❤️ for more
🔰Programming Languages🔰
1. JAVA:
More than 85% android apps are created using JAVA. It is also used in big (big means big) websites. It is a portable programming language which makes it easy to use on multi platforms.
2. Java Script:
Its a browser/client side language. It makes the webpage more interactive. Like for example when you enter a comment on Facebook then the whole page doesn’t load., just that comment is added. This kind of functionalities are added into webpages with JavaScript. Javascript brought about a revolution in webapps.
3. Assembly Language:
The most low level programming language because its nothing more than machine code written in human readable form. Its hard to write and you need to have deep understanding of computers to use this because you are really talking with it. Its very fast in terms of execution.
4. C:
Its a low level language too that’s why its fast. It is used to program operating system, computer games and software which need to be fast. It is hard to write but gives you more control of your computer.
5. C++ :
Its C with more features and those features make it more complex.
6. Perl:
A language which was developed to create small scripts easily . Programming in Perl is easy and efficient but the programs are comparatively slower.
7. Python:
Perl was made better and named Python. Its easy, efficient and flexible. You can automate things with python in a go.
8. Ruby:
Its similar to Python but it became popular when they created a web application development framework named Rails which lets developers to write their web application conveniently.
9. HTML and CSS:
HTML and CSS are languages not programming languages because they are just used display things on a website. They do not do any actual processing. HTML is used to create the basic structure of the website and then CSS is used to make it look good.
10. PHP:
It is used to process things in a website. It is server-sided language as it doesn’t get executed in user browser, but on the server. It can be used to generate dynamic webpage content.
11. SQL:
This is not exactly a programming language. It is used to interact with databases.
➡️ This list could be long because there are too many programming language but I introduced you to the popular ones.
❓Which Language Should Be Your First Programming Language?
✅ Suggestions..
1. Getting Started
Learn HTML & CSS. They are easy and will give you a basic idea of how programming works. You will be able to create your own webpages. After HTML you can go with PHP and SQL, so will have a good grasp over web designing and then you can go with python, C or Java. I assure you that PHP, HTML and SQL will be definitely useful in your hacking journey.
2. Understanding Computer And Programming Better
C..The classic C! C is one of the most foundational languages. If you learn C, you will have a deep knowledge of Computers and you will have a greater understanding of programming too, that will make you a better programmer. You will spend most of your time compiling though (just trying to crack a joke).
3. Too Eager To Create Programs?
Python! Python is very easy to learn and you can create a program which does something instead of programming calculators. Well Python doesn’t start you from the basics but with if you know python, you will be able to understand other languages better. One benefit of python is that you don’t need to compile the script to run it, just write one and run it.
React ❤️ for more
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Tools & Tech Every Developer Should Know ⚒️👨🏻💻
❯ VS Code ➟ Lightweight, Powerful Code Editor
❯ Postman ➟ API Testing, Debugging
❯ Docker ➟ App Containerization
❯ Kubernetes ➟ Scaling & Orchestrating Containers
❯ Git ➟ Version Control, Team Collaboration
❯ GitHub/GitLab ➟ Hosting Code Repos, CI/CD
❯ Figma ➟ UI/UX Design, Prototyping
❯ Jira ➟ Agile Project Management
❯ Slack/Discord ➟ Team Communication
❯ Notion ➟ Docs, Notes, Knowledge Base
❯ Trello ➟ Task Management
❯ Zsh + Oh My Zsh ➟ Advanced Terminal Experience
❯ Linux Terminal ➟ DevOps, Shell Scripting
❯ Homebrew (macOS) ➟ Package Manager
❯ Anaconda ➟ Python & Data Science Environments
❯ Pandas ➟ Data Manipulation in Python
❯ NumPy ➟ Numerical Computation
❯ Jupyter Notebooks ➟ Interactive Python Coding
❯ Chrome DevTools ➟ Web Debugging
❯ Firebase ➟ Backend as a Service
❯ Heroku ➟ Easy App Deployment
❯ Netlify ➟ Deploy Frontend Sites
❯ Vercel ➟ Full-Stack Deployment for Next.js
❯ Nginx ➟ Web Server, Load Balancer
❯ MongoDB ➟ NoSQL Database
❯ PostgreSQL ➟ Advanced Relational Database
❯ Redis ➟ Caching & Fast Storage
❯ Elasticsearch ➟ Search & Analytics Engine
❯ Sentry ➟ Error Monitoring
❯ Jenkins ➟ Automate CI/CD Pipelines
❯ AWS/GCP/Azure ➟ Cloud Services & Deployment
❯ Swagger ➟ API Documentation
❯ SASS/SCSS ➟ CSS Preprocessors
❯ Tailwind CSS ➟ Utility-First CSS Framework
React ❤️ if you found this helpful
Coding Jobs: https://whatsapp.com/channel/0029VatL9a22kNFtPtLApJ2L
❯ VS Code ➟ Lightweight, Powerful Code Editor
❯ Postman ➟ API Testing, Debugging
❯ Docker ➟ App Containerization
❯ Kubernetes ➟ Scaling & Orchestrating Containers
❯ Git ➟ Version Control, Team Collaboration
❯ GitHub/GitLab ➟ Hosting Code Repos, CI/CD
❯ Figma ➟ UI/UX Design, Prototyping
❯ Jira ➟ Agile Project Management
❯ Slack/Discord ➟ Team Communication
❯ Notion ➟ Docs, Notes, Knowledge Base
❯ Trello ➟ Task Management
❯ Zsh + Oh My Zsh ➟ Advanced Terminal Experience
❯ Linux Terminal ➟ DevOps, Shell Scripting
❯ Homebrew (macOS) ➟ Package Manager
❯ Anaconda ➟ Python & Data Science Environments
❯ Pandas ➟ Data Manipulation in Python
❯ NumPy ➟ Numerical Computation
❯ Jupyter Notebooks ➟ Interactive Python Coding
❯ Chrome DevTools ➟ Web Debugging
❯ Firebase ➟ Backend as a Service
❯ Heroku ➟ Easy App Deployment
❯ Netlify ➟ Deploy Frontend Sites
❯ Vercel ➟ Full-Stack Deployment for Next.js
❯ Nginx ➟ Web Server, Load Balancer
❯ MongoDB ➟ NoSQL Database
❯ PostgreSQL ➟ Advanced Relational Database
❯ Redis ➟ Caching & Fast Storage
❯ Elasticsearch ➟ Search & Analytics Engine
❯ Sentry ➟ Error Monitoring
❯ Jenkins ➟ Automate CI/CD Pipelines
❯ AWS/GCP/Azure ➟ Cloud Services & Deployment
❯ Swagger ➟ API Documentation
❯ SASS/SCSS ➟ CSS Preprocessors
❯ Tailwind CSS ➟ Utility-First CSS Framework
React ❤️ if you found this helpful
Coding Jobs: https://whatsapp.com/channel/0029VatL9a22kNFtPtLApJ2L
❤5👍2
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
ENJOY LEARNING 👍👍
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
ENJOY LEARNING 👍👍
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15+ Must Watch Movies for Programmers🧑💻🤖
1. The Matrix
2. The Social Network
3. Source Code
4. The Imitation Game
5. Silicon Valley
6. Mr. Robot
7. Jobs
8. The Founder
9. The Social Dilemma
10. The Great Hack
11. Halt and Catch Fire
12. Wargames
13. Hackers
14. Snowden
15. Who Am I
Happy Coding ♥️
1. The Matrix
2. The Social Network
3. Source Code
4. The Imitation Game
5. Silicon Valley
6. Mr. Robot
7. Jobs
8. The Founder
9. The Social Dilemma
10. The Great Hack
11. Halt and Catch Fire
12. Wargames
13. Hackers
14. Snowden
15. Who Am I
Happy Coding ♥️
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10 Chrome Extensions Every Developer Should Use
✅ JSON Viewer – Beautify and view JSON data instantly
✅ Wappalyzer – Identify the tech stack of any website
✅ Web Developer – Adds powerful dev tools to your browser
✅ ColorZilla – Pick and copy any color from a webpage
✅ React Developer Tools – Debug and inspect React components
✅ Dark Reader – Enable dark mode on every site
✅ Session Buddy – Manage tabs and sessions like a pro
✅ WhatFont – Instantly identify fonts on websites
✅ Lighthouse – Audit performance, SEO, and accessibility
✅ AI Prompt Genius – Manage and save prompts for AI tools
React with your favorite emoji if you found a gem in here!
✅ JSON Viewer – Beautify and view JSON data instantly
✅ Wappalyzer – Identify the tech stack of any website
✅ Web Developer – Adds powerful dev tools to your browser
✅ ColorZilla – Pick and copy any color from a webpage
✅ React Developer Tools – Debug and inspect React components
✅ Dark Reader – Enable dark mode on every site
✅ Session Buddy – Manage tabs and sessions like a pro
✅ WhatFont – Instantly identify fonts on websites
✅ Lighthouse – Audit performance, SEO, and accessibility
✅ AI Prompt Genius – Manage and save prompts for AI tools
React with your favorite emoji if you found a gem in here!
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PREPARING FOR AN ONLINE INTERVIEW?
10 basic tips to consider when invited/preparing for an online interview:
1. Get to know the online technology that the interviewer(s) will use. Is it a phone call, WhatsApp, Skype or Zoom interview? If not clear, ask.
2. Familiarize yourself with the online tools that you’ll be using. Understand how Zoom/Skype works and test it well in advance. Test the sound and video quality.
3. Ensure that your internet connection is stable. If using mobile data, make sure it’s adequate to sustain the call to the end.
4. Ensure the lighting and the background is good. Remove background clutter. Isolate yourself in a place where you’ll not have any noise distractions.
5. For Zoom/Skype calls, use your desktop or laptop instead of your phone. They’re more stable especially for video calls.
6. Mute all notifications on your computer/phone to avoid unnecessary distractions.
7. Ensure that your posture is right. Just because it’s a remote interview does not mean you slouch on your couch. Maintain an upright posture.
8. Prepare on the other job specifics just like you would for a face-to-face interview
9. Dress up like you would for a face-to-face interview.
10. Be all set at least 10 minutes to the start of interview.
10 basic tips to consider when invited/preparing for an online interview:
1. Get to know the online technology that the interviewer(s) will use. Is it a phone call, WhatsApp, Skype or Zoom interview? If not clear, ask.
2. Familiarize yourself with the online tools that you’ll be using. Understand how Zoom/Skype works and test it well in advance. Test the sound and video quality.
3. Ensure that your internet connection is stable. If using mobile data, make sure it’s adequate to sustain the call to the end.
4. Ensure the lighting and the background is good. Remove background clutter. Isolate yourself in a place where you’ll not have any noise distractions.
5. For Zoom/Skype calls, use your desktop or laptop instead of your phone. They’re more stable especially for video calls.
6. Mute all notifications on your computer/phone to avoid unnecessary distractions.
7. Ensure that your posture is right. Just because it’s a remote interview does not mean you slouch on your couch. Maintain an upright posture.
8. Prepare on the other job specifics just like you would for a face-to-face interview
9. Dress up like you would for a face-to-face interview.
10. Be all set at least 10 minutes to the start of interview.
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