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What if you check every pair of strings (bruteforce)?
For every two strings, check if they can form a puzzle by comparing their last and first words.
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The problem requires the final list of merged phrases to be returned in lexicographical order. After generating all valid combinations, sorting ensures the output follows the expected order regardless of the generation sequence.
Problems like Before and After Puzzle reflect common interview themes such as string manipulation, hash maps, and efficient pairing logic. While the exact problem may vary, similar patterns frequently appear in technical interviews at large tech companies.
The optimal approach uses hash maps to track phrases by their first and last words. This allows you to quickly find phrases that can be combined without checking every possible pair. Results are stored in a set and later sorted to meet the output requirements.
Hash tables are the most useful data structure because they allow efficient lookup of phrases based on starting or ending words. A set is also helpful to remove duplicate merged phrases before sorting the final results.