Frequently asked questions

Spaced-repetition practice for LeetCode, built on FSRS. It's a companion to LeetCode, not a mirror of it: you solve on leetcode.com, and U-Leet² decides what you re-solve and when so the problems you care about actually stick.

Only metadata — title, difficulty, tags, slug, number. Never the problem statement. Every problem deep-links out to leetcode.com.

Because on the "What did you lean on?" question you picked My notes or Editorial — anything other than None. By design, a Rating measures whether the approach came back to you unaided, not whether your submission was Accepted. So if you needed a hint, the Rating is forced to Again no matter which button you press.

If you actually solved it cold, choose None and your Again/Hard/Good/Easy stands.

Correct. Editorial-then-Accepted is still a Lapse. Rating = unaided retrieval of the approach.

The Card enters a short relearning step (about 10 minutes) and comes back the same day before returning to normal scheduling with reduced stability. The note field opens focused so you can jot what tripped you up while it's fresh — it's optional and never blocks you moving on.

Everything keys off a server-computed due timestamp (a client can never fake it). The session queue simply pulls Scheduled Cards where due <= now.

• New-to-me Cards sit in the Backlog and are dripped into the schedule at your New Cards per day cap, oldest-added first. On promotion they're due immediately — and their first encounter is a Learn.
• Already-solved Cards skip the drip: they're scheduled at intake with ~7 days of stability but a short 2-day verify interval, so they come due in 2 days to confirm the claim.
• After that, FSRS owns the date. Every Review recomputes the next due server-side.

It did, but on a ~10-minute relearning step, so its due is later today. It won't bounce into the queue instantly.

New Cards per day, not Reviews per day. The new-card cap is the rate the Backlog enters your schedule; that's the binding constraint on how busy future days get.

Pre-filled with your last note, and there's one note per Card — so saving overwrites it. Treat it as a living cheat sheet you refine over time.

Your prior notes/solutions are hidden behind that control during a Review. Revealing them is recorded on the attempt (and is a form of using help).

The Next 7 days forecast shows reviews coming due over the week, so you can see a heavy day before it arrives and pace yourself — instead of discovering an overdue mountain afterward.

LeetCode tags like "Array" or "Hash Table" describe where the data lives, not a technique you can be weak at. Mastery rolls up by Pattern (the actual skills), so "weakest" points you at something to drill.

Averaged across your Cards. A Card only counts fully once it reaches Mastered.

If you've been away and a pile of Cards is overdue, the app spreads them across several days at your cap and works through the ones you're most likely to still recover first (salvageability order) — rather than showing a wall of "overdue: 60." The raw overdue count is deliberately never shown.

The hour your practice-day rolls over (default 4am). Your day runs, e.g., 4am → 4am instead of midnight → midnight, so a late-night session at 1am counts toward the previous day — it won't break your streak or double-bill your daily caps. Set it to whenever you actually stop for the night.

It's a type-to-search field, not a classic dropdown — there are 400+ timezones, which would be an unusable <select>. Click it and type a city or region (e.g. Manila, Sydney, New_York), then pick the match.

• Reviews per day — the most Cards a session will ask you for in a day.
• New Cards per day — how fast the Backlog drips into rotation (the real workload dial).
• Desired retention — how much you want to remember at review time (0.7–0.97). Higher = more reviews, and a re-solve here costs ~30 minutes.

Changes take effect on the next queue you open.

Yes — Settings → Export as JSON gives you every Card, Review, note, and solution, no strings attached.

No. Not affiliated with, endorsed by, or sponsored by LeetCode. Problem statements are never stored here.