Spent the first few minutes just clarifying what 'differences' meant because it's actually kind of vague.
Clarify the definition of 'differences' (e.g., character-level edits, mismatched positions, or set differences) and the expected output format. Then propose an efficient algorithm, such as using two pointers for positional differences or dynamic programming for edit operations, and analyze time/space complexity.
Pro tip: At Meta, interviewers value candidates who proactively discuss trade-offs and edge cases (e.g., Unicode, empty strings) and who write clean, testable code. Always ask clarifying questions before diving into a solution.
Ask the interviewer to define 'differences' (e.g., character mismatches, insertions/deletions, or set differences) and the desired output format (e.g., list of indices, edit script, or set of characters).
Based on the definition, select an appropriate algorithm: two-pointer for positional differences, dynamic programming (edit distance) for edit operations, or set operations for character set differences.
State the time and space complexity of your chosen approach and discuss potential optimizations or trade-offs (e.g., memory vs. speed).
Consider edge cases such as empty strings, different lengths, Unicode characters, and case sensitivity. Explain how your solution handles them.
Write clean, modular code and walk through examples to verify correctness. Be prepared to discuss testing strategies.
AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.