The ambiguity part took me a second to fully internalize.
Clarify the problem constraints (e.g., input format, dictionary, output order) and then propose a backtracking solution that recursively explores all possible word segmentations. Discuss trade-offs like time complexity and potential optimizations such as memoization or pruning with a dictionary.
Pro tip: Mention that this is essentially a word break problem with multiple solutions, and that using a trie or hash set for dictionary lookups can significantly speed up the backtracking. Also, consider handling edge cases like empty input or no valid decodings.
Ask about input format (e.g., string with spaces as word separators), dictionary availability, expected output order, and constraints on input size. Confirm whether the Morse code mapping is standard and if the dictionary is provided.
Explain that you will recursively try all possible word lengths at each position, checking if the substring is a valid word in the dictionary. If valid, recurse on the remainder and build the result.
Analyze time complexity (exponential in worst case) and propose optimizations like memoization to avoid recomputing subproblems, or using a trie for efficient prefix lookups. Mention pruning invalid paths early.
Address empty input, no valid decodings, and multiple spaces. Discuss how to build the output list and whether to return all solutions or just count them.
Walk through a small example to demonstrate correctness, such as decoding '...' with a given dictionary. Show how the recursion explores possibilities and produces all valid strings.
AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.