Spaced repetition for LeetCode

Solve it once. Still know it in the interview.

Patternwell watches your solves, rates them on what actually happened, and brings each problem back right before you'd forget it.

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leetcode.com/problems/daily-temperatures

DescriptionEditorialSolutionsSubmissions

739. Daily Temperatures

Medium

For each day in a list of temperatures, work out how many days you'd wait until a warmer one. If no warmer day comes, the answer is 0.

Hint 1⌄

Think about which days are still waiting for an answer.

Hint 2⌄

Hint 3⌄

TestcaseResult

Accepted

48 / 48 test cases passed · 18 min

Submit

Patternwellre-solve

Accepted. How did it go?

!Opened hint 1 of 3

!1 wrong submission

✓No editorial, no solutions

Again1d

Hard4d

Good11d

Easy26d

Saved as Hard. Back in 4 days.

Other revision tools trust the button you press. Patternwell checks it against the hints you opened, your wrong submissions and the time you took. So the schedule follows what you really remember.

01 · Every morning

One short list. Then you're done.

Open the extension and see exactly what's due and how long it takes. Set a daily limit and the list never grows past it.

02 · Quick reviews

Most reviews take 90 seconds, not 40 minutes.

You get a short description in our words with the title hidden. Name the pattern and the complexity, then check. Full re-solves come only when they matter.

03 · Pattern memory

Interviews test patterns. So does Patternwell.

It knows how well you remember each of 24 patterns, not just each problem. A fading pattern gets a short drill before it slips.

04 · Interview day

A handful of reviews keeps a problem for months.

Without review, memory fades. Each well-timed review resets it and buys more time. Tell Patternwell your interview date and it plans for that week.

Today · Tue 14 Oct4 due

4 reviews · about 9 min

Problem 1 Medium

quick review · title hidden

2 min

Problem 2 Easy

quick review · title hidden

2 min

Heap / Top-K drill

pattern drill · 3 look-alikes

3 min

Course Schedule

re-solve on LeetCode

Re-solve

Quick review · 1 of 20:41

Given a string, find the length of the longest stretch with no repeated character.

Pattern

Sliding WindowTwo PointersPrefix SumStack

Time

O(n)O(n log n)O(n²)

3. Longest Substring Without Repeating CharactersGood · back in 21 days

Pattern memory24 tracked

Hash Map96%

Two Pointers92%

Binary Search86%

Tree DFS83%

Monotonic Stack71%

Union-Find54%

drill todayUnion-Find, last coded 38 days ago

Recall over 60 days · one problem

with Patternwellsolved once

The engine

An engine that does the remembering for you.

Patternwell runs FSRS-6, the open-source scheduler behind modern Anki, with our own layer on top that thinks in patterns and checks every rating. We tested it the hard way.

5.6×

Fresher patterns. In a 90-day simulation of the roadmap, no pattern went more than 12 days without being coded. Scheduling problems one by one let some drift for 67 days. Same time per day.

400/400

Exact maths. Our FSRS-6 matched the reference implementation on all 400 test cases, agreeing to 14 decimal places.

92.4%

More kept on busy days. With only 8 reviews a day, Patternwell held 92.4% of the whole deck, against 90.1% for a plain due-date list. Averaged over 60 simulated runs.

Grounded in research

Spacing and retrieval practice are among the best-replicated results in learning science (Cepeda et al., 2008; Latimier et al., 2021).

Learns you

After 400 reviews, the scheduler can be fitted to your own memory, and it only switches if the fit predicts you better.

Checkable

Stats show predicted recall against what really happened, so you never have to take our word for it.

How it compares

Reminders tell you when. Patternwell checks what you remember.

Feature	Fixed reminders	Self-rated tools	Patternwell
Tracks your solves automatically	—	some	✓
Schedule adapts to your memory	—	✓	✓
Rating checked against what happened	—	—	✓
Memory per pattern, not just per problem	—	—	✓
90-second reviews with the title hidden	—	—	✓
Solutions hidden while you re-solve	—	editor reset	✓
Planned around your interview date	—	—	✓

Pricing

Free to track everything. Pro costs less than one coffee a month.

Free

₹0

Free everywhere

Up to 150 problems
Honest ratings and quick reviews
Daily limit and 4-week forecast
10 drills a week

Start free

Pro yearly ₹25 a month

₹300/ year

$12 outside India

Unlimited problems
Re-solve mode with solutions hidden
Timed interview mode
Unlimited drills
Interview-date planning
Calendar feed and morning email

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Pro monthly

₹50/ 30 days

$2 outside India

Everything in Pro
For the last weeks before interviews
Doesn't renew by itself

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Full refund within 7 days, no questions asked. Founding lifetime: ₹999 ($29) once, for the first 200 people.

Why this exists

I kept re-solving problems I'd "done" months earlier and still blanking. The tools I tried let me rate a solve Easy right after reading the editorial. Patternwell is the revision system I built for my own prep, made honest enough to trust.

— the founder

Questions

Before you install

Does it read my code?

No. It only notices that you submitted, the verdict, the hints you opened, which tabs you visited and how long you were active.

I've already solved 200 problems.

Import them in one go. They're spread over the coming weeks so day one isn't a wall of reviews.

What's FSRS?

The open-source scheduler behind modern Anki, built from hundreds of millions of real reviews. Ours is checked against the reference on 400 test cases.

Is this made by LeetCode?

No. Patternwell is independent and works alongside it. Quick reviews use descriptions we write ourselves, never LeetCode's text.

Stop re-learning what you already learned.

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