As an interviewer who likes asking about them... I'd say they're surprisingly useful. - Barring very degenerate inputs, prefix tries are usually faster than `s

As an interviewer who likes asking about them... I'd say they're surprisingly useful. - Barring very degenerate inputs, prefix tries are usually faster than `std::set<std::string>`. And for longer strings, prefix tries are definitely faster than `std::unordered_set<std::string>`. - The same ideas that apply to strings apply to bitvectors too, so we can handle arbitrary binary data the same way. (This gives us things like Patricia trees.) - They're great for implementing immutable sets. In fact most functional languages use some variant of prefix tries for their set/map data structures. And some real-world use cases: - Symbol lookup in mach-O (macOS) binaries use prefix tries - One of the fastest string sorting algorithms (burstsort) uses prefix tries - Program analysis / abstract interpretation really benefits from immutable sets of bitvectors with fast union operations - Pretty sure every typeahead / autocomplete implementation uses some kind of trie - And for something a bit more esoteric: scrabble/boggle AIs use them too