The mod 26 part is where I fumbled initially.
Clarify the signature definition and edge cases (empty string, single character). Then design an algorithm that computes the signature for each string and uses a hash map to group strings by their signature. Analyze time and space complexity, and discuss potential optimizations or alternative approaches.
Pro tip: Mention that the signature can be represented as a string of characters (e.g., by adding 'a' to each delta) to simplify hashing and comparison. Also, consider using a rolling hash for very long strings to save space, but note the trade-off with collision risk.
Confirm the definition of shift distance signature, including modular arithmetic and handling of edge cases like empty or single-character strings.
For each string, compute its signature by iterating through adjacent characters and calculating the modular difference. Use a hash map to group strings with identical signatures.
Calculate time complexity: O(N * L) where N is number of strings and L is average length. Space complexity: O(N * L) for storing signatures and groups.
Consider representing signatures as strings or using rolling hashes to reduce memory. Discuss trade-offs between collision risk and space savings.
Walk through a small example to verify correctness, including edge cases like empty strings and strings with identical signatures but different characters.
AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.