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Interviews
Core Problems
Master the 15 essential patterns that form the foundation of almost every technical interview.
Blind 75
The definitive list of 75 most essential problems curated for top-tier FAANG preparation.
All Problems
Explore our comprehensive library of 140+ algorithmic challenges with multi-language support.
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.
Step 1 / 17
Speed: 1.0x
Visualizing Subarray Sum Growth
2
idx 0-1
idx 13
idx 2-4
idx 32
idx 4Best Subarray Found (Overall Max)
Current Subarray (Running Total)
Record Max SubSum2
System Initialization
Step 1 of 17
Algorithm commentary
Step 1: Initialization. We set
maxSub to the first element (2) and initialize curSum to 0. The goal is to find a contiguous range with the highest sum.typescript
Initializing...
Variables
index_iN/A
value_nN/A
curSum0
bestMax2
bestRange[0, 0]
Launch Your DSA Mastery
Experience high-octane interview sprints, targeted corporate practice maps, and connected roadmaps designed to wow modern developers.
BOOTCAMP TRACK
7-Day Bootcamp
7-Day Blind 75 Sprint
Have an interview next week? Master the 75 most essential, high-frequency DSA questions in exactly 7 structured, gamified days. Complete 10-11 questions daily with active, step-by-step pointers.
Weekly Syllabus Schedule
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Start Your Journey Topic-Wise
Click on any category cell inside our visual learning map to load high-impact problem nodes. Master arrays, pointers, trees, and dynamic graphs connected dynamically.
Topic-Wise Categories
Not sure where to begin? We recommend starting with our15 Core Patterns Track
Interactive Code Playground
Experiment with algorithmic structures and step-by-step visualizations in real time directly from your browser.
Interactive Coding Workspace
A seamless environment to write, debug, and visualize your code in real-time, built for the modern developer.
Integrated code runner with instant feedback and test previews
Interactive visualizations that sync with your code execution
Pro-grade editor with syntax highlighting and custom shortcuts
Stuck in thinking? Try our Thinkpad
Sometimes code isn't enough. Our built-in Thinkpad lets you draw, sketch, and take notesalongside 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
Thinkpad Canvas
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
TELEMETRY
Case 1
nums = [-2,1,-3,4,-1,2,1,-5,4]Expected: 6Got: ?
Case 2
nums = [5,4,-1,7,8]Expected: 23Got: ?
Case 3
nums = [1]Expected: 1Got: ?
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Rulcode.com is the culmination of this experience and knowledge, created to help fellow engineers prepare efficiently and confidently for technical interviews.
Rulcode.com is the culmination of this experience and knowledge, created to help fellow engineers prepare efficiently and confidently for technical interviews.
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