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Problem Understanding
Restate the problem in your own words.
Design Yelp / Nearby Friends
Design a Yelp-class location-search service: 'find restaurants within 2 km, filter by cuisine + rating, sort by distance'. A geo-indexed POI database (10M+ businesses globally), full-text search on names/categories, ranking by relevance + distance, and review aggregation as a side table. The hard parts are the geo-index (geohash / S2 / quadtree / H3), keeping listings fresh, and serving the same query from neighbours’ phones with cache reuse.
- YelpReviews-first POI directory; the canonical ‘nearby + reviews’ product.
- Google Maps PlacesBuilt-in to Maps; Knowledge Graph signals + opening hours + popular times.
- TripAdvisorTravel-focused — hotels + restaurants + attractions; same geo + reviews shape.
- FoursquareOriginally a check-in app, now powering many third-party POI APIs.
Your task: read the problem above, then write what the system is, who uses it, the rough scale, and the headline UX expectation — in your own words. Submit for AI review when you're ready.
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