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Visualize, Understand, Code & Masteryour technical interviews.

The all-in-one interactive platform for modern technical interviews. From Data Structures & Algorithms and Frontend to System Design and SQL — master every domain with step-by-step visual animations, an intuitive scratchpad, and hands-on code execution.

Join engineers from Google, Meta, OpenAI, and top tech companies cracking their coding interviews.

Solve a problem now Go Pro

Features

Visualizer

Interactive Tree, Graph, and Table data explorers

Roadmap

Structured learning milestones guiding your journey from basics to advanced interview topics.

System Design

Architectural fundamentals covering scaling, caching, databases, and distributed systems.

Frontend

JavaScript, TypeScript polyfills, DOM challenges, and frontend interview essentials.

Database (SQL)

Interactive SQL queries, schema design, and real-world database problem sets.

DSA Fundamentals

In-depth visual guides and cheat sheets covering Big-O complexity and data structures.

Join our growing community

Have questions or feedback? We're building RulCode for you. Join our social platforms and help us shape the future of tech prep.

Your dream job is absolute worth it !

Frequently Asked Questions

Everything you need to know about Rulcode.com

Topic Roadmap

Follow the structured prerequisite flow of DSA topics and track your completion status across every pattern.

Engineers trust us with their job interviews

See how our interactive platform has helped developers master Data Structures & Algorithms and ace their technical interviews.

"The interactive visualizations completely changed how I approach data structures. It makes learning DSA so much simpler and more intuitive. I finally cleared my technical rounds with confidence!"

Sarah Johnson

Senior Software Engineer

"I've tried many platforms, but this is by far the most practical. The step-by-step animations help you visualize the logic rather than just memorizing code. Highly recommended for anyone struggling with algorithmic thinking."

Michael Chen

Software Development Engineer II

"The focus on patterns rather than just grinding random problems is a game changer. The platform breaks down complex topics into digestible chunks. It was instrumental in helping me secure my new role."

Emily Rodriguez

Frontend Engineer

"A must-have resource for interview preparation. The clean UI and interactive scratchpad make practicing a breeze. It guided me through the core patterns effectively and made the learning process actually enjoyable."

David Kim

Full Stack Developer

"Before this, dynamic programming was a nightmare. The visual walkthroughs demystified it completely. It's the best investment I've made in my career development and interview prep."

Jessica Patel

Technical Lead

"The platform's structured approach to teaching core patterns is phenomenal. You don't just learn the solution; you learn how to arrive at it. Thanks to this, I breezed through my coding rounds."

Alex Mercer

Software Engineer

Learn by Visualization

Visualize, Understand and Solve

Watch Kadane's algorithm slide over contiguous ranges in lockstep motion. Observe live as the running sum decides whether to grow or reset from scratch at each array index, while updating the record-breaking maximum sum in real-time.

Local vs. Global Maxima

Observe currentSum resets to zero when running sums become negative, avoiding sub-optimal ranges.

Contiguous Window Trace

Watch the active subarray boundaries dynamically stretch as positive integers expand the sum.

State Console Tracking

Inspect running variables like curSum and bestMax change line-by-line as code runs.

Try the Visual Playground

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Stuck in thinking? Try our Thinkpad

Sometimes code isn't enough. Our built-in Thinkpad, powered by your favorite drawing tool Excalidraw, lets you draw, sketch, and take notes alongside complex algorithms before you start typing. It's the perfect tool for when you need to visualize logic that's hard to hold in your head.

Infinite canvas for free-form sketching and drawing

Rich note-taking alongside your problem workspace

Perfect for dry-running tree and graph traversals

Save and reference your logic while you code

Try Thinkpad

Thinkpad Canvas

A practice question bank with everything you'd ever need

Master data structures and algorithms across critical topics and top tech companies. Every question is paired with step-by-step interactive visualizations, hints, and optimized solutions to help you ace your interviews.

200+ questions

Lifetime access

More questions coming soon for this topic.

Interactive Code Playground

Experiment with algorithmic structures and step-by-step visualizations in real time directly from your browser.

Instant Feedback & Complexity Analysis

Go beyond simple correctness. RulCode analyzes your implementation in real-time, helping you optimize for both time and space complexity as you write.

Automated test suites for every problem

Real-time complexity estimations

Detailed edge-case diagnostics

Multi-language support for all solutions

Try Code Runner

TELEMETRY

Case 1nums = [-2,1,-3,4,-1,2,1,-5,4]

Expected: 6Got: ?

Pending

Case 2nums = [5,4,-1,7,8]

Expected: 23Got: ?

Pending

Case 3nums = [1]

Expected: 1Got: ?

Pending

Python▾

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