Design a Typeahead Service on an In-Memory Trie, Then Scale It Without New Services
Company: Pinterest
Role: Software Engineer
Category: System Design
Difficulty: hard
Interview Round: Onsite
Overview: Design a typeahead autocomplete service that starts at a modest scale using an in-memory keyword trie, then scale it out without adding external services. It tests trie internals and keyword storage, read and write paths, score updates, rebuilds with hot swaps, and sharding strategy trade-offs.
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