Fixed-Size Sliding Window
As a Senior engineer, explain Fixed-Size Sliding Window. What problem does it solve and how would you describe it in an interview?
Answers use simple, clear English.
Quick interview answer
At Senior depth: start with the problem, then mechanism, then a short example. Maintain a window of size k; slide by adding the right element and subtracting the left.
Detailed answer
At Senior depth: start with the problem, then mechanism, then a short example. Maintain a window of size k; slide by adding the right element and subtracting the left. Ideal for max/min/average of every contiguous subarray of length k. Core: Maintain a window of size k; slide by adding the right element and subtracting the left. Ideal for max/min/average of every contiguous subarray of length k. Real-time example: Network monitor: max bytes/sec over any 60-second rolling window from per-second samples. Pros: O(n) single pass; avoids recomputing overlapping segments from scratch. Cons: Only applies when window size is fixed; variable windows need expand/shrink logic. Common mistakes: Off-by-one on window bounds; forgetting to seed the first window before sliding. Best practices: State window size k explicitly; track running aggregate incrementally. Audience level: Senior.
Full explanation
Maintain a window of size k; slide by adding the right element and subtracting the left. Ideal for max/min/average of every contiguous subarray of length k.
Real example & use case
Network monitor: max bytes/sec over any 60-second rolling window from per-second samples.
Pros & cons
Pros: O(n) single pass; avoids recomputing overlapping segments from scratch. Cons: Only applies when window size is fixed; variable windows need expand/shrink logic.
Common mistakes
Off-by-one on window bounds; forgetting to seed the first window before sliding.
Best practices
State window size k explicitly; track running aggregate incrementally.
Follow-up questions
Open one as its own read / solve / listen card