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Hint 2 — locked

Hint 3 — locked

Problem

Build a search autocomplete service like Google's search bar. As the user types each character, the system must return the top-10 most relevant completions within 100 ms. A background pipeline keeps the suggestion index fresh as content is published.

Functional Requirements

• Return top-10 prefix-matched suggestions per keystroke (< 100 ms)
• Rank suggestions by popularity + recency
• Support prefix-matching on billions of indexed terms
• Index updated within 5 minutes of new content
• Graceful degradation: stale suggestions beat no suggestions

Non-Functional

• 10B autocomplete queries per day (heavy read)
• p99 suggestion latency < 100 ms
• Index updates propagate within 5 minutes
• Must degrade gracefully — serve stale data on index failure