My approach was iterative: scan for ';', then check all possible keys to see if one matched at that position.
First, clarify the token format and requirements, noting the inconsistency between the question's ':x:' and the description's ';' and ':'. Then, design a robust solution using a delimiter-based encoding scheme (e.g., length-prefix or escaping) to handle arbitrary strings, and implement encode/decode with careful parsing. Discuss trade-offs between simplicity and robustness, and consider edge cases like empty strings and special characters.
Pro tip: Demonstrate foresight by addressing the ambiguity in the token format upfront and proposing a solution that handles arbitrary input safely, showing you prioritize correctness and clarity in real-world scenarios.
Ask clarifying questions about the token format, allowed characters, and whether the mapping is provided. Confirm if the encoding must be reversible for any input.
Select a delimiter-based encoding that avoids ambiguity, such as length-prefixing or escaping special characters. Explain why a naive delimiter approach can fail.
Write the encode function that converts a list of strings into a single string using the chosen strategy, ensuring it handles edge cases like empty strings and special characters.
Write the decode function that parses the encoded string back into the original list, validating the format and handling errors gracefully.
Walk through test cases (e.g., empty list, strings with delimiters) and discuss time/space complexity and alternative approaches.
AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.