It was a follow-up, so I was already a bit drained from whatever came before.
First, clarify the problem details and constraints, then discuss a brute-force approach before optimizing. For encoding/decoding, consider using a delimiter or length-prefix to handle arbitrary strings, and analyze time/space complexity. Implement cleanly with edge cases in mind.
Pro tip: Mention that you would discuss trade-offs between different encoding schemes (e.g., delimiter vs. length-prefix) and choose based on constraints like character set and performance. Also, proactively test with edge cases like empty strings and special characters.
Ask about input types, character set, size limits, and whether the encoded string needs to be human-readable. Confirm if the encoding must be reversible and if there are any restrictions on delimiters.
Start with a simple approach like concatenating strings with a delimiter, then identify its flaws (e.g., delimiter collision). Propose a robust method like length-prefixing or escaping.
Outline the steps for encoding (e.g., for each string, append its length followed by a delimiter and the string) and decoding (parse length, then read that many characters). Handle edge cases like empty strings.
State time and space complexity (usually O(n) for both). Discuss trade-offs: length-prefix is robust but less readable; delimiter with escaping is readable but more complex.
Write clean code with meaningful variable names. Walk through examples, including edge cases like empty list, strings with delimiters, and Unicode characters.
AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.