All Puzzles

Prepare for
Interview

100+ High-Quality Logic Challenges

The Goal

Brainfuck is designed to be the ultimate resource for interview preparation. We provide free access to complex puzzles that are frequently asked in Quant, HFT, and SDE interviews at top firms.

The Legacy

We credit the legendary Brainstellar.com as our primary source of inspiration. We have updated and curated this collection to help modern developers and quantitative analysts succeed in their job search.

100% Free Access

Every puzzle and solution is completely free. We believe quality educational resources should be accessible to everyone preparing for their career.

Zero Tracking

Your preparation is private. We use local storage to track your progress, meaning your data never leaves your device. No login required.

High Fidelity

All solutions are meticulously checked for accuracy and clarity, ensuring you learn the underlying logical principles needed for HFT and SDE roles.

Open Community

Join the discussion on any puzzle to see alternative solutions, share insights, and connect with others preparing for similar roles.

Start Your Prep

Browse the archive, mark your progress, and conquer your next technical interview with confidence.