Hey devs!
If you're grinding through coding interviews, you've probably been there: solving problem after problem on LeetCode, feeling prepared, only to blank out when it matters. That's exactly what happened to me. I crushed over 200 problems, but bombed five interviews in a row. The issue? Not lack of practice, but terrible retention.
In this post, I'll break down why one-and-done grinding fails, the science behind better learning, and the tool I built to automate it all. Let's dive in.
The Forgetting Curve: Why Your Brain Betrays You
Your brain isn't a hard drive — it forgets fast. According to the Ebbinghaus forgetting curve, we lose about 70% of new information within 24 hours if we don't review it. I was solving problems daily, but by interview time, most of that knowledge evaporated.
Think about it: Cramming 200 problems might give you a temporary boost, but without reinforcement, patterns like dynamic programming or graph traversals fade. In interviews, I could recognize the problem type but forgot the edge cases or optimizations. One-and-done practice = guaranteed forgetting.
The Solution: Spaced Repetition
Enter spaced repetition — a proven technique where you review material at increasing intervals to combat forgetting. It's like this:
- Day 1: Learn/solve
- Day 3: Quick review
- Week 1: Deeper dive
- Week 2: Test yourself
- Month 1: Solidify
This is the same method med students use for anatomy or pharmacology. Studies show it can boost retention by 200-300% compared to massed practice. For coding, it means turning fleeting "aha" moments into automatic pattern recognition.
I needed this for DSA prep, but tracking reviews manually across LeetCode was a nightmare. So, I built my own system.
Introducing DSAPrep: Automated Spaced Repetition for LeetCode
I created DSAPrep.dev — a free web app that integrates spaced repetition directly into your LeetCode workflow. No more spreadsheets or forgotten reviews; it handles the scheduling for you.
Key Features
Mark Problems Complete: Link your LeetCode solves and flag them done in one click.
Auto-Scheduled Reviews: The app uses algorithms to schedule reviews at optimal intervals based on Ebbinghaus principles.
Adaptive Difficulty: Rate how tough a problem felt (easy/medium/hard), and it adjusts intervals — struggle more? Review sooner.
Daily Dashboard: Log in to see exactly what's due today. Solve, review, repeat.
Progress Tracking: Visualize retention with stats on completed reviews and mastery levels.
It's seamless: Solve on LeetCode, log in DSAPrep, and let it manage the rest. No manual tracking required.
Tech Stack
Built with:
- Frontend: React for a responsive, interactive UI.
- Backend: Node.js for handling scheduling logic and user data.
- Database: MongoDB for storing problem logs, schedules, and ratings.
I made it free because interview prep is stressful enough without paywalls.
My Results: From 30% to 85% Retention
Before DSAPrep: 200+ problems solved, but retention hovered around 30%. Interviews felt like starting over.
After: Focused on 80 problems with spaced reviews. Retention jumped to ~85% (self-tracked via mock interviews). Patterns like two-pointer techniques or binary search trees became second nature.
The difference? In one interview, a tricky sliding window problem popped up — I'd reviewed it just a week prior via DSAPrep. Nailed it without panic.
Why This Works for Any Dev
Spaced repetition isn't magic; it's science-backed efficiency. If you're prepping for FAANG or startups, this shifts you from quantity to quality. Less burnout, more confidence.
Try it out at https://dsaprep.dev. Open to feedback — bug reports, feature ideas (like integration with other platforms), or even collab requests.
What's Your Biggest Interview Prep Challenge?
Retention? Nerves? System design? Drop a comment below — let's chat and level up together. Happy coding! 🚀
Top comments (1)
Next, I will post about how the algo works!