Interview prep for every round.
Guided lessons, step-by-step visualizations, practice problems, and timed mock interviews for coding, system design, behavioral, and AI engineering, from your first Big-O to an AI system design round.
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Two Pointers (Intro)
Algorithms, lesson 7 of 40Put one pointer at each end of a sorted array. If the pair adds up to too much, move the right pointer left. Too little, move the left pointer right. Repeat until they meet.
- Sorted order is what makes each move safe.
- Each pointer only moves inward, so no pair is checked twice.
- The same idea solves pair-sum and palindrome questions.
1 + 13 = 14 is larger than 12, so move R one step left.
Write it, then run the tests
pairSum.js- ·pairSum([1, 3, 4, 6, 8, 10, 13], 12)not run
- ·pairSum([2, 7, 11, 15], 9)not run
- ·pairSum([1, 2, 3], 7)not run
In the pair-sum algorithm on a sorted array, the current sum is less than the target. Which pointer moves, and which way?
Precision Engineered Learning
DSA Curriculum
Work through Foundations, Data Structures, and Algorithms in a guided sequence with visualizations and interactive labs.
System Design and Behavioral
Design systems the way interviewers probe them, and structure behavioral stories with the STAR method.
AI Engineering
Prepare for AI engineering interviews on LLMs, RAG, agents, and evaluation, with rubrics and timed mock interviews.
Practice Problems
Solve real coding challenges in-browser with difficulty filters, progress tracking, and instant feedback.
Code References
Official code snippets and curated question banks. Production grade templates for interviews, learning, and quick reference.
Community
Explore articles, interview experiences, and problems shared by a global network of engineers.
The Architectural Journey
A structured roadmap from core logic and data structures to system design, behavioral rounds, and AI engineering.
01. Foundations
Master the underlying mechanics of computational logic and efficiency.
02. Data Structures
Build and manipulate the blueprints that organize digital information.
03. Algorithms
Apply high-level strategies to solve complex computational problems.
04. Practice Problems
Solve real coding challenges filtered by difficulty, topic, and status with instant feedback.
05. System Design
Learn to architect scalable, reliable systems from load balancing to database sharding and beyond.
06. Behavioral Interviews
Master the STAR method, leadership principles, and common behavioral questions at top tech companies.
Prepare for AI engineering interviews: build with LLMs, ground answers with retrieval, and evaluate and ship AI features you can trust.
Interview Prep for AI Engineers
Prepare for interviews for roles that build with large language models: prompting and structured output, embeddings and retrieval, RAG, tool calling and agents, evaluation, security, and running AI features in production.
66 questions in 17 topics
Each with a study guide, hints, a reference answer, and a rubric to score yourself.
7 interview rounds
From the technical screen to AI system design, each with a timed mock interview.
Hands-on exercises
Predict outputs, diagnose failures, and solve linked practice problems in Python or JavaScript.
A track for team and tech leads
Plan an AI rollout, review a team-built automation, and lead the response when AI errors reach customers.
Design a support assistant with citations and measurable quality.
1. Ingest help articles: chunk by heading, keep the article ID and version.
2. Retrieve with hybrid search, rerank, and answer only from the top passages.
3. Cite every claim, and say so when nothing relevant was retrieved.
4. Measure retrieval recall and answer faithfulness on a labeled set.
Problem framing
Correctness
Evidence or testing
Trade-offs
Communication
8 of 10, ready
Ready means 8 or more with no zero.
Hands-on Problem Solving
Solve real coding challenges in-browser. Web-based execution works instantly for guests. Write, run, and refine your logic without ever touching a terminal.
Instant Web Runtime
Vanilla JS/TS, React, and Vue playgrounds run directly in-browser for zero-friction exploration.
Multi-Language Lab
Unlock Python, Java, C, C++, Go, Ruby, and PHP execution with a free account.
01 02 03 04 05 06 07 08 09 10
function findMaxSubarray(arr) { let maxSoFar = arr[0]; let currentMax = arr[0]; for (let i = 1; i < arr.length; i++) { currentMax = Math.max(arr[i], currentMax + arr[i]); maxSoFar = Math.max(maxSoFar, currentMax); } return maxSoFar; }
Execution
12ms
Memory
4.2MB
Test Passed
Solution optimized for time complexity O(n).
Data Structures & Algorithms, Animated
Static code hides what's actually happening. Step through pushes, swaps, and traversals frame by frame to see the state changes that build real intuition.
View all visualizationsCompare BFS and DFS traversal strategies
Stack frames track function calls
Traverse nodes pointer by pointer
Euclidean algorithm computes GCD step by step
Self-balancing rotations in action
Evict the least recently used entry
Beyond the Curriculum
Access production-grade code snippets and curated question banks for immediate use in your projects and interviews.
Code Snippets
Ready-to-use implementations of common patterns. From binary search templates to graph traversals, find the template you need in seconds.
Question Bank
Curated question bundles for interview prep. Explore real-world experiences shared by developers who've been there.
Learn from the Community
Join engineers sharing real-world insights. Discover interview experiences, solve community problems, and eventually contribute your own knowledge.
Developer Insights
Read articles on algorithms, system design, and real-world engineering challenges.
Interview Experiences
Learn from real interview stories shared by developers at top companies.
Creator Monetization
Grow from a learner to a contributor. Share content and sell bundles on the same platform.
AI Help While You Learn
AI-powered guidance built into your learning workflow: hints, explanations, and support without leaving the platform. Bring your own Anthropic, OpenAI, or Google API key. Your key is stored only in your browser, and you pay the provider directly with no markup.
Ask AI for Hints
Get contextual explanations and nudges when you're stuck on a problem or lesson concept.
On-Demand Guidance
AI support is embedded in lessons and problems. No context switching to external tools.
Bring Your Own Key
Plug in your personal Anthropic, OpenAI, or Google API key once. It is stored only in your browser, sent encrypted with each AI request, and never saved on our servers.
Pay Providers Directly
No markup. AI calls run through your own API key and bill straight to your Anthropic, OpenAI, or Google account.
Your Knowledge Has Value
Go from learning to earning on the same platform. Share what you know, build your reputation, and monetize your expertise.
Create Content
Write articles, build coding problems, share code snippets, publish question bundles, or share interview experiences.
Grow Your Audience
Your content is discoverable by the entire community. Build credibility and a following around your expertise.
Monetize Your Work
Set your price on eligible content. Earn revenue directly when other users purchase your problems or question bundles.
Track & Withdraw
Monitor your earnings in real-time from your wallet dashboard. Request payouts when you reach the minimum threshold.
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Browse all free lessons
Easy & Medium AI Engineering questions
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Everything in Explorer
Save progress & dashboard
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Personalized analytics
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Publish community content
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Frequently Asked Questions
Yes! Explore lessons, problems, snippets, and community content for free without creating an account. Create a free account to save progress, track analytics, and unlock additional features. Premium is a one-time payment for full access.
Yes. The AI Engineering track prepares you for interviews for roles that build with large language models: prompting and structured output, embeddings and retrieval, RAG, tool calling and agents, evaluation, security, and running AI features in production. Each question comes with a study guide, an interview question to answer with hints, a reference answer, and a rubric to score yourself. Interview Practice covers seven interview rounds, from the technical screen and live coding to AI system design and leadership scenarios, each with a timed mock interview.
Three groups: software engineers preparing for coding, system design, and behavioral rounds who now also face AI questions; engineers preparing for AI engineering roles that build LLM features, RAG, tool calling and agents, evaluation, security, and serving; and team and tech leads who adopt AI without being AI engineers, with the AI for Team and Tech Leads topic and a Leadership Scenarios interview round.
Web languages run in-browser instantly: Vanilla JS/TS, React, Vue, and static HTML/CSS/JS. With an account, you can also write and execute Python, Java, C, C++, Go, Ruby, and PHP using our compiler infrastructure.
Six tracks: Foundations (Big-O, recursion, memory), Data Structures (arrays, trees, graphs, hash maps), Algorithms (sorting, searching, dynamic programming, greedy), System Design (scalability, distributed systems, case studies), Behavioral Interviews (the STAR method, leadership, conflict), and AI Engineering (LLMs, RAG, agents, evaluation, production). Plus practice problems, code snippets, and question banks for interview prep.
Yes. CodeSnatch includes a dedicated System Design track with fundamentals, case studies, and advanced topics covering scalability, distributed systems, caching, databases, networking, and real-world architecture patterns. Each lesson is structured around the trade-offs interviewers actually probe.
Yes. The Behavioral Interview track teaches the STAR method, common competency questions, leadership principles, and how to structure stories that hit hiring signals. You get worked examples, practice prompts, and feedback patterns used by senior engineers at top companies.
CodeSnatch goes beyond problem grinding. You get structured lessons with interactive code labs, algorithm visualizations, AI-powered hints, real interview experiences from developers, a community where you can publish content, and the ability to monetize your expertise by selling problems, question bundles, and more. It's a complete ecosystem: learn, practice, share, and earn in one platform.
Yes! Premium members can publish paid community content like coding problems, question bundles, code snippets, and articles. You set your price, earn revenue when others purchase your content, and manage payouts from your wallet dashboard.
AI-powered hints and explanations are built into lessons and practice problems. You can ask for contextual guidance when stuck, without leaving the platform, and get AI feedback on your written AI Engineering answers. AI runs on your own Anthropic, OpenAI, or Google API key (see the next question), so you pay the provider directly at their published rates with no markup from us.
Yes, and it's the only AI path on CodeSnatch. Any authenticated user can plug in a personal Anthropic, OpenAI, or Google API key from the Settings page (Member or Premium, no upgrade required). AI requests are powered by your key and you pay the upstream provider directly at their published rates. Your key is stored only in your browser, transmitted to our server only as an encrypted per-request header, used in memory to issue that single provider call, and discarded afterwards. We never write your API key to a database, log, or analytics tool. You can remove the key at any time from Settings.
Nope! You can browse lessons, problems, community content, and use web playgrounds without an account. Create a free account when you want to save progress, use analytics, access the review queue, contribute to the community, or use compiler languages.
Premium is a one-time payment that unlocks all premium lessons and problems, every AI Engineering question, problem solutions and all hints, unlimited community contributions, the ability to create and sell paid content, premium avatars, and bonus compiler tokens.
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Structured prep for coding, system design, behavioral, and AI engineering interviews, with real problems and a community of engineers. Everything you need for your next interview.
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