Choose an Offset for Compressing Clustered Integers with Outliers
Quick Overview
Choose an offset for clustered integer compression using a maximum-coverage sliding window. Make the codec reversible and account for bit width, outlier markers, metadata, and the limits of coverage-only optimization.
Choose an Offset for Compressing Clustered Integers with Outliers
Company: Headlands
Role: Software Engineer
Category: Software Engineering Fundamentals
Difficulty: hard
Interview Round: Technical Screen
Most integers in a dataset are concentrated in a narrow range, with a few outliers. Choose an offset that reduces storage, and explain how a sliding window can identify a useful range.
### Clarifying Questions
The compact bit width, outlier encoding, signedness, metadata cost, and exact storage objective are unspecified. For the worked analysis, choose a fixed w-bit unsigned offset code with a separate inlier/outlier indicator, and store outliers in a wider representation. The offset is stored once per block. These are explicit codec assumptions, not supplied requirements.
### What a Strong Answer Covers
A reversible encoding, the range covered by an offset, a maximum-coverage window algorithm, complete storage accounting, and the difference between selecting an offset for fixed width and optimizing the width itself.
### Follow-up Questions
- What changes if one compact code value is reserved as an escape marker?
- When could offset metadata make compression larger than the original data?
Overview: Choose an offset for clustered integer compression using a maximum-coverage sliding window. Make the codec reversible and account for bit width, outlier markers, metadata, and the limits of coverage-only optimization.
Most integers in a dataset are concentrated in a narrow range, with a few outliers. Choose an offset that reduces storage, and explain how a sliding window can identify a useful range.
Clarifying Questions Guidance
The compact bit width, outlier encoding, signedness, metadata cost, and exact storage objective are unspecified. For the worked analysis, choose a fixed w-bit unsigned offset code with a separate inlier/outlier indicator, and store outliers in a wider representation. The offset is stored once per block. These are explicit codec assumptions, not supplied requirements.
What a Strong Answer Covers Guidance
A reversible encoding, the range covered by an offset, a maximum-coverage window algorithm, complete storage accounting, and the difference between selecting an offset for fixed width and optimizing the width itself.
Follow-up Questions Guidance
What changes if one compact code value is reserved as an escape marker?
When could offset metadata make compression larger than the original data?