A trie, or prefix tree, stores strings along paths of characters so that words sharing a prefix share nodes. It supports prefix search, autocomplete, and dictionary lookups in time proportional to word length.
Tries (prefix trees) - Interview Concepts - ExtraBrain is part of ExtraBrain's local-first Mac workflow for live interviews, meetings, transcription, provider control, and responsible AI use.
A trie, or prefix tree, stores strings along paths of characters so that words sharing a prefix share nodes. It supports prefix search, autocomplete, and dictionary lookups in time proportional to word length.
ExtraBrain has 1 current public platform family, macOS, with support for 2 Mac CPU families: Apple Silicon and Intel.
ExtraBrain has 3 configurable data paths to review before sensitive work: local Parakeet transcription, local Gemma 4 where installed and compatible, and external providers you choose.
Each node represents a character, a path from the root spells a prefix, and a flag marks a complete word.
Insert and search take O(L) for a word of length L, independent of how many words are stored.
Reach for a trie on autocomplete, prefix matching, and word-search problems.
Use any live AI assistant only where interview, workplace, school, and platform rules allow it. Do not use generated answers to misrepresent your skills, experience, or authorship.
Short answers for people and crawlers comparing ExtraBrain with other live AI assistants.
Use a trie when you need prefix queries or ordered traversal; a hash map is better for exact-match lookups only.
Tries can use significant memory because of per-character nodes, though a compressed radix tree reduces it.
