LeetO(n)

Stop grinding, start understanding! Ace your next technical interview with LeetO(n), the smartest way to practice LeetCode-style problems on the go.

Whether you're in line for coffee or on your daily commute, turn your downtime into productive prep time. We've distilled essential coding problems into a few effective learning formats:

Flashcard Mode: Refresh your memory on key problem insights. Each card presents a problem and lets you flip to reveal the optimal solution and key takeaways. Perfect for quick review sessions.

Guidance Mode: Don't just memorize solutions—master them. This mode asks you a series of guided questions to help you deconstruct each problem and build the core logic yourself.

Recap Mode: Test your understanding, don't just memorize. We challenge you to identify the correct approach, time complexity, or code snippet for a given problem.

Features:

Curated Problem Sets: Study by topic! We’ve organized hundreds of problems covering everything from Arrays and Strings to Trees, Graphs, and Dynamic Programming.

Track Your Progress: See your strengths and weaknesses at a glance. Our stats help you focus your efforts on the topics that need the most work.

Favorites: Bookmark tough problems to easily revisit them later. Show More