Reverse Linked List
Design a small subsystem that relies on Reverse Linked List. Outline components, data flow, failure modes, and metrics.
Answers use simple, clear English.
Quick interview answer
Use Reverse Linked List as the core idea. Example shape: Undo stack in a text editor implemented as singly linked list needs in-place reversal for replay..
Detailed answer
Use Reverse Linked List as the core idea. Example shape: Undo stack in a text editor implemented as singly linked list needs in-place reversal for replay.. Watch for: Recursive version O(n) stack; doubly linked needs both pointer updates.. Measure success via latency/error/saturation. Core: Iterative: prev=None, curr=head; save next, point curr.next=prev, advance. Recursive variant uses head as new tail after reversing rest. Real-time example: Undo stack in a text editor implemented as singly linked list needs in-place reversal for replay. Pros: O(n)/O(1) iterative; tests pointer discipline fundamentals. Cons: Recursive version O(n) stack; doubly linked needs both pointer updates. Common mistakes: Losing reference to next before rewiring; returning wrong node (old head vs new head). Best practices: Draw three pointers; return prev as new head after loop. Audience level: Engineering Manager.
Full explanation
Iterative: prev=None, curr=head; save next, point curr.next=prev, advance. Recursive variant uses head as new tail after reversing rest.
Real example & use case
Undo stack in a text editor implemented as singly linked list needs in-place reversal for replay.
Pros & cons
Pros: O(n)/O(1) iterative; tests pointer discipline fundamentals. Cons: Recursive version O(n) stack; doubly linked needs both pointer updates.
Common mistakes
Losing reference to next before rewiring; returning wrong node (old head vs new head).
Best practices
Draw three pointers; return prev as new head after loop.
Follow-up questions
- How would you test Reverse Linked List?
- What metrics prove Reverse Linked List is healthy in prod?
- How does Reverse Linked List change at 10× traffic?