Welcome back, there.
Pick up where you left off.
Placement prep, mapped.
CS theory, DSA, recursion and DP, SQL, aptitude, system design, ML and the NeetCode 150 — sequenced like a course, with in-browser coding in C, C++, Java and Python.
590 topics & problems · 361 coding problems · 10 modules
10 modules, one path
CS Theory
Operating systems, DBMS, computer networks and OOP — the four subjects every placement interview checks.
DSA Basics
Ninety problems that build loop, array and string fluency — from warm-ups to exam-level questions.
Recursion & Memoization
Learn to write recursion yourself, then turn it into memoized DP step by step. No memorising. Java only.
Story Problems
Ninety-four long-form problems written like real online-assessment questions, grouped by the pattern they hide.
SQL
Seventy questions on one realistic database, run on a real PostgreSQL engine inside your browser.
Aptitude
Quantitative, logical and verbal aptitude by topic, with formula sheets, worked solutions and timed mocks.
System Design
The building blocks of large systems and the classic interview case studies, drawn out step by step.
Machine Learning
From the maths to transformers — the ML you need for data science, ML engineering and AI roles.
NeetCode 150
The 150 problems that cover every interview pattern, explained from brute force to optimal, with NeetCode's video for each.
Cheat Sheets
Every subject on one page. For the last hour before a test or an interview.
Built for the way placements actually work
Run code in your browser
C, C++, Java and Python compile and run right on the page. No installs, no waiting for a server, verdicts in a second.
Video walkthroughs
Every CS Theory lesson and every NeetCode 150 problem comes with a hand-picked video next to the written explanation, so you can read or watch.
Watch recursion run
Step through Java recursion line by line and see the call stack, the recursion tree and the memo table change. System design and theory topics come with zoomable diagrams too.
Real SQL practice
A full Postgres engine runs in your browser. Write queries against a real schema and get checked instantly.
Timed aptitude mocks
Topic-wise practice sets with worked solutions, then full mock tests under exam timing.
Progress that remembers
Pick up where you left off on any device. Your dashboard shows exactly what is left in every module.
Questions
Is any of it free?
Yes. CS Theory (OS, DBMS, Networks, OOP) is completely free, and every other module has free lessons and problems at the start so you can see the quality before paying.
Which languages can I code in?
C, C++, Java and Python (the Recursion & Memoization module is Java only, by design). Everything compiles and runs inside your browser on a laptop or desktop. On phones you can read every problem, explanation and solution.
How is this different from free YouTube playlists?
Everything is sequenced, written up properly, tested and connected: notes, diagrams, a curated video, practice problems with hidden tests, quizzes and progress tracking in one place.
Can I get a refund?
No. All sales are final, which is why so much of the site is free to try first. Please read the free lessons before you buy.