Putting It All Together

A production trie/autocomplete system layers:

Beyond:

• Persistent tries: stored on disk; lazy-load nodes. Used by JOSE, RocksDB.
• Concurrent tries: lock per branch, or copy-on-write.
• Suffix tries / suffix arrays: indexing all suffixes for substring search.
• DAWG (Directed Acyclic Word Graph): merge equivalent subtries to save memory. Used by Scrabble dictionaries.

Real systems where you'll see them:

• IDE auto-import suggestions (TypeScript, Rust)
• Browser address bar suggestions
• IP routing in Linux kernel
• DNS suffix matching
• Lucene FST (finite state transducer) — like a radix tree but with arbitrary outputs

You've now built the canonical version.