Linked List Cycle
easyblind-75dsalinked-listtwo-pointers
Asked at
Amazon, Google, LinkedIn, Meta, Microsoft
Problem statement
Implement hasCycle for the classic Linked List Cycle problem.
This Blind 75 version is framed for frontend interviews: write clean JavaScript, name the invariant out loud, and handle edge cases without over-engineering.
What this tests
- Pattern:
Floyd cycle detection. - Ability to explain time and space complexity clearly.
- Careful handling of empty inputs, duplicates, and boundary cases.
- Production-style JavaScript readability, not just competitive-programming shortcuts.
Requirements & constraints
- Use JavaScript without external libraries.
- Prefer the standard optimal interview approach for this pattern.
- Return deterministic output when multiple valid outputs exist where the prompt implies ordering.
Examples
Example 1
Input: Use the canonical Blind 75 sample for this problem.
Output: Return the value required by the problem statement.
How to approach Linked List Cycle
The strategy an interviewer expects you to reach for.
Senior Frontend Approach Start by identifying the pattern: Floyd cycle detection. Then define the invariant the loop or recursion maintains before writing code.
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