Find the Longest Common Digit Prefix Across Two Arrays
Company: Hudson River Trading
Role: Software Engineer
Category: Software Engineering Fundamentals
Difficulty: medium
Interview Round: Technical Screen
Given two arrays of positive integers, convert each integer to its decimal string representation and find the maximum length of a common prefix between any number in the first array and any number in the second array.
### Constraints & Assumptions
- Numbers are non-negative or positive integers.
- Prefix comparison is string-based decimal comparison.
- Return the maximum prefix length, not the pair itself.
- Input sizes may be large enough to require better than all-pairs comparison.
### Clarifying Questions to Ask
- Can numbers be zero?
- Should leading zeroes ever appear in input strings?
- Do we need to return the matching pair?
- What are the maximum array sizes?
- Can arrays be empty?
### What a Strong Answer Covers
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### Follow-up Questions
- How would you return all pairs with the maximum prefix?
- How would memory change for very long strings?
- Could sorting both arrays solve this?
- How would duplicates affect the answer?
Quick Answer: This Hudson River Trading software engineering question tests efficient detection of the longest common digit prefix across two arrays. It helps candidates practice string conversion trade-offs, prefix data structures, and complexity analysis for numeric inputs.