Track your study streak, review queue, and learning path.
Sections with the lowest completion rates. Strengthen these to boost interview readiness.
Complete a few problems to reveal your weak areas.
Step-through lessons on scale, capacity math (QPS, memory, latency), distributed tradeoffs, and classic design interviews. Completion saves as sd_completed; spaced review uses sd_last_review (1d / 3d / 7d).
No SD lessons due for review.
Open system design hub →No problems due for review. Complete more to build your queue.
Spaced repetition helps long-term retention. After you complete problems, they enter the review queue. Revisit them when due to strengthen recall.
Hide the code and type the solution yourself. Build muscle memory for interviews.
Complete 3 problems from memory (blind mode + Type It verify) in a row. No peeking.
How many problems you've completed per algorithmic pattern.
Estimated from problems completed and review sessions.
Start with Two Sum!