Linked List Cycle
A easy-tier problem at 53% community acceptance, tagged with Hash Table, Linked List, Two Pointers. Reported in interviews at Yahoo and 19 others.
Linked List Cycle is labeled easy but catches candidates off guard because the obvious brute-force approach wastes space, and the trick isn't obvious until you've seen it. Yahoo, Intel, Oracle, and Cisco all ask it. With a 53% acceptance rate, roughly half the people who attempt it either time out, use too much memory, or miss the two-pointer pattern entirely. If this lands in your assessment and you blank on Floyd's cycle detection, StealthCoder surfaces the working solution in seconds while you stay invisible to the proctor.
Companies that ask "Linked List Cycle"
Linked List Cycle is the kind of problem that decides whether you pass. StealthCoder reads the problem on screen and surfaces a working solution in under 2 seconds. Invisible to screen share. The proctor sees nothing. Built by an Amazon engineer who realized the OA tests how well you memorized 200 problems, not how well you code.
Get StealthCoderThe problem asks you to detect if a linked list contains a cycle. Most candidates jump to a hash table solution, storing visited nodes and checking membership. That works but burns O(n) space. The real pattern is the slow and fast pointer technique: move one pointer one step at a time and another two steps at a time. If they meet, there's a cycle. If the fast pointer hits the end, there isn't. It's elegant and O(1) space, which interviewers prefer. The trap is overthinking it or defaulting to the hash table without realizing the constraint. When you hit this live and your first instinct feels inefficient, StealthCoder runs in the background and hands you the pointer-based solution so you can paste and move forward.
Pattern tags
You know the problem.
Make sure you actually pass it.
Linked List Cycle recycles across companies for a reason. It's easy-tier, and most candidates blank under the timer. StealthCoder is the hedge: an AI overlay invisible during screen share. It reads the problem and surfaces a working solution in under 2 seconds. Built by an Amazon engineer who realized the OA tests how well you memorized 200 problems, not how well you code. Works on HackerRank, CodeSignal, CoderPad, and Karat.
Linked List Cycle interview FAQ
Is Linked List Cycle actually easy or do companies just label it that way?+
It's labeled easy because the algorithm is simple once you know it. The two-pointer trick is a single insight. But acceptance sits at 53%, meaning candidates either don't know the pattern or second-guess themselves under time pressure. If you've drilled it, it's trivial. If you haven't, it's a time sink.
Which approach do interviewers want: hash table or two pointers?+
Two pointers. It's O(1) space versus O(n), and at companies like Oracle, Cisco, and Intel, space efficiency matters. Hash table is a valid fallback if you're stuck, but mentioning the tortoise and hare algorithm first signals you know the standard solution.
Is this still asked at FAANG and big tech?+
Yes. Companies in the top 10 here include Oracle, Cisco, Intel, Qualcomm, and SAP. Linked list cycle is a canonical problem. It shows up in screening rounds because it's quick to implement and separates candidates who know the pattern from those who don't.
What if I can't remember Floyd's algorithm on the day?+
Draw it out. Two pointers, one moves one step, one moves two. Write pseudocode. If panic sets in and you're blank, that's exactly when StealthCoder runs invisibly and gives you a working implementation so you can paste and explain your way forward.
How does this relate to the other linked list topics?+
Hash Table and Two Pointers are the two competing approaches. This problem teaches the tradeoff: memory for speed, or elegance for efficiency. Mastering both methods here unlocks other linked list problems at companies like Yahoo, EPAM, and Autodesk.
Want the actual problem statement? View "Linked List Cycle" on LeetCode →