Clarify the problem and edge cases, then propose using a hash map where the key is the shift pattern (e.g., a tuple of differences mod 26) and the value is a list of strings. Discuss time and space complexity, and consider optimizations like using a string representation of the pattern.
Pro tip: Mention that you can avoid modulo operations by using a fixed-size array or string for the pattern, and highlight that the pattern is invariant to the starting character, which is key to grouping.
Restate the problem in your own words and confirm details: strings match if the differences between consecutive characters modulo 26 are identical. Ask about edge cases like empty strings, single-character strings, and non-lowercase letters.
Propose using a hash map to group strings by their shift pattern. For each string, compute the pattern as a tuple of differences (mod 26) between consecutive characters, and use it as the key.
State that the time complexity is O(N * L) where N is the number of strings and L is the average length, and space complexity is O(N * L) for storing the patterns and groups.
Discuss how to handle empty strings (pattern is empty tuple), single-character strings (pattern is empty tuple, so all single-character strings group together), and ensure modulo arithmetic works for all characters.
Mention potential optimizations like using a string representation of the pattern to avoid tuple overhead, or using a rolling hash. Also, consider if the input is large and if streaming is possible.
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