My first instinct was to brute force it by comparing prefixes pairwise and I actually started explaining that out loud before catching myself.
Clarify the problem and edge cases, then propose a trie-based solution that inserts all words and for each word finds the shortest prefix that is unique to it. Discuss time and space complexity, and consider alternative approaches like sorting.
Pro tip: Mention that building a trie allows efficient prefix checks and that you can mark nodes with a count of how many words pass through them to quickly identify unique prefixes. Also, discuss how to handle the case where a word is a prefix of another, ensuring the longer word gets a prefix longer than the shorter word.
Restate the problem in your own words and ask clarifying questions about input constraints, word distinctness, and expected output format.
Discuss brute-force, sorting, and trie-based solutions, highlighting trade-offs in time and space complexity.
Explain how to build a trie where each node tracks the number of words passing through it, then for each word traverse until finding a node with count 1.
State that building the trie takes O(N*L) time and O(N*L) space, where N is the number of words and L is the average length, and finding prefixes takes O(N*L) time.
Discuss cases where a word is a prefix of another, ensuring the longer word gets a prefix longer than the shorter word, and cases with single-word lists.
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