Intermediate~2h
Linked List in Data Structures & AlgorithmsInterview Readiness Check
Fast/slow pointer tricks — cycle detection, midpoint, k-th from end, reversal in O(1) space.
fast slowFloyd'scyclereversemerge sortedk-th from end
Learning path
Try a sample question
Detect a cycle in a linked list. Given a list that may loop back to an earlier node. Which approach detects a cycle in O(n) time and O(1) space?
A.Store all visited nodes in a HashSet — if you see the same node twice, there's a cycle
B.Count nodes and compare to an expected length
C.Floyd's cycle detection: slow pointer moves 1 step, fast pointer moves 2 steps. If they meet, there's a cycle. If fast reaches null, no cycle.
D.Reverse the list and check if the head changes
Sign up free to take the full check and see the answer with an explanation.
What this module tests
- Conceptual understanding of linked list fundamentals
- Trade-offs and design decisions in real system scenarios
- fast slow and Floyd's — applied knowledge
- Interview-style reasoning and explanation quality
Free to start
Take the Linked List check →
10 questions · Dimension scoring · AI coach feedback · Shareable result
Test your knowledge — free →No credit card · Takes 10–15 min
Frequently asked questions
- What does the Linked List check test?
- The check covers fast/slow pointer tricks — cycle detection, midpoint, k-th from end, reversal in o(1) space. Questions span beginner to advanced difficulty and test both conceptual understanding and practical trade-off reasoning.
- What keywords should I know for Linked List?
- Key concepts include: fast slow, Floyd's, cycle, reverse, merge sorted, k-th from end. These frequently appear in data structures & algorithms interviews at product and infrastructure companies.
- How many questions are in the check?
- Each check has 10 questions — a mix of MCQ and short-answer. You get scored by dimension (e.g., scalability, consistency) so you know exactly where to focus.
- How long does it take to study Linked List?
- Most engineers spend around 2 hours on this module. The check itself takes about 10–15 minutes. You can retake it up to 3 times per day.
- What prerequisite knowledge do I need before Linked List?
- Linked List builds on Two Pointers. Complete those first for the best results.
- Is fast slow, Floyd's, cycle covered?
- Yes. The Linked List module covers fast slow, Floyd's, cycle among other key concepts. The check includes questions that reflect real data structures & algorithms interview patterns.