Linked List problems,
and the tell.
The input is nodes joined by pointers and the answer rearranges them, not their values. 56 problems in the catalogue carry this tag, from first-week easy to interview hard.
Free to start. Running and submitting a solution never costs credits.
How the pattern actually works.
One mechanism, and the mistake that costs people the problem.
The tell. The input is nodes joined by pointers and the answer rearranges them, not their values.
The mechanism. Almost everything is a pointer dance: a dummy head so the first node is not a special case, one slow and one fast pointer to find the middle or a cycle, and careful reversal in place.
What goes wrong. Losing the rest of the list. Save the next pointer before you overwrite it.
The ones asked most often.
By how often the catalogue records them being set, not by our opinion.
- LRU CacheMediumasked at 101 companies
- Max StackHardasked at 4 companies
- Find the Minimum and Maximum Number of Nodes Between Critical PointsMediumasked at 2 companies
- Add Two Numbers IIMediumasked at 1 companies
- Linked List in Binary TreeMediumasked at 1 companies
- Copy List with Random PointerMediumasked at 17 companies
- Middle of the Linked ListEasyasked at 5 companies
- Maximum Twin Sum of a Linked ListMediumasked at 1 companies
- Reorder ListMediumasked at 5 companies
- Design HashSetEasyasked at 1 companies
Read it, watch it, then solve it.
The order that makes a pattern stick.
Everything in the app, in one place.
Practice, interviews and the tools, all free to start. Swipe to see the rest.
DSA practice
Problems filed under the pattern that solves them, not a sheet.
352 problemsOpenCompany sets
Practise what one company actually asks, the week before the round.
463 companiesOpenCoding interview
Pick the role, write in a real editor, and answer while you type.
scored reportOpenMock interviews, spoken
You answer out loud, it follows up on what you said.
36 topicsOpenDatabase round
DBMS asked the way a panel asks it: indexes, joins, normal forms.
in Core CSOpenOOP round
Inheritance, polymorphism and the follow-up you never rehearse.
in Core CSOpenSystem design
How real systems are built, from the primitives to the AI stack.
27 chaptersOpenSQL practice
Real schemas, your query, the rows it returns, and an honest verdict.
39 questionsOpenAptitude
Quant, logical, verbal, DI and technical, timed like the real test.
280 questionsOpenOnline assessment
A clock, marks per question and hidden tests, like a company's judge.
37 papersOpenAlgorithm visualiser
Watch it run on your own input, one step at a time.
26 algorithmsOpenAI that helps, not solves
Hints one at a time, AI review before a mentor reads it.
100 free creditsOpenResume builder
Build it inside the app, next to the work you practised.
in the appOpenProgress and readiness
One score, and the axis you are weakest on.
tracked dailyOpen
Free to start: 100 AI credits when you sign up and 100 every month. Start free in the app
About linked list problems.
Free to start, no card.
Start practisingHow do I know a problem is a linked list problem?
The input is nodes joined by pointers and the answer rearranges them, not their values.
How many linked list problems should I solve?
Enough to stop needing the hint, which is usually ten to fifteen across the levels, not the whole list. The catalogue tags 56, split roughly 11 easy, 38 medium and 7 hard in the sample we show, so work up rather than across.
What goes wrong most often in linked list problems?
Losing the rest of the list. Save the next pointer before you overwrite it.
Is practising by pattern better than a problem sheet?
A sheet tells you what to solve. A pattern tells you why those problems sit together, which is the part that carries over to the problem you have not seen. That is why the app files every problem under its pattern.