Learn DSA by seeing how algorithms think.
Build intuition through guided lessons, interactive visualizations, pattern-based practice, and revision tools.
No signup required. Sign in only to sync notes and progress.
function binarySearch(arr, target) { let low = 0, high = arr.length - 1; while (low <= high) { const mid = Math.floor((low + high) / 2); if (arr[mid] === target) return mid; if (arr[mid] < target) low = mid + 1; else high = mid - 1; } return -1;}nums[mid] = 5 is less than the target, so the left half is discarded -- the answer must be to the right.
What do you want to do today?
Pick a clear route into DSA.
The homepage stays intentionally simple. Full lessons, filters, practice links, and pattern checklists live on dedicated pages.
Beginner Learning Path
Build strong foundations from arrays and hashing to trees, graphs, and dynamic programming.
Start PathTopic Library
Explore focused lessons, visualizations, quizzes, and practice problems by topic.
Browse LibraryPattern Mastery
Learn how to recognise common problem-solving patterns and apply them across different questions.
How learning works
Learn, think, visualize, practice.
Every topic is designed to connect the idea, the reasoning, and the execution state, so you are not just memorising code.
Learn
Start with the idea, the brute-force baseline, and the clue that makes the better approach possible.
Think
Build the mental model: what state matters, what stays true, and why each decision is safe.
Visualize
Replay code, state, call stack, output, and timeline together until the algorithm feels predictable.
Practice
Use quizzes, notes, references, and practice links to turn one solved problem into a reusable pattern.
Code, state, stack, and explanation stay in sync.
The simulator precomputes algorithm steps into a timeline, so learners can play, pause, step backward, and replay the reasoning without the UI recomputing the algorithm on every render.
The middle value is too small, so every index on the left can be removed from the search space.
Platform proof
Built for understanding, not noise.
Beginner paths, pattern paths, and focused topic tracks.
Step-through visualizers with timeline replay.
Your local progress updates as you learn.
Pattern thinking
Master the patterns behind many interview questions.
Keep the detailed checklist off the homepage, but make the next step obvious for learners ready to move beyond individual topics.