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USection 01URL Shortener
Problem Understanding
Restate the problem in your own words.
What this step looks like in a real interview: Read the problem statement and real-world examples, then write what the system is, who uses it, and the scope you'd commit to in a 45-minute round.
ProblemWhat you're designing
URL Shortener
Asked atAmazon· SDE2Google· L4Microsoft· L62
Design a URL-shortening service. Map long URLs to short ids (6–8 chars), resolve id → long URL for redirect. Support custom aliases, TTL, and click analytics. Id generation must be collision-safe and the read path must be cheap (O(1) lookup, cache-friendly).
Real-world examples
- Bit.lyOriginal URL shortener.
- TinyURLLifetime free links.
- t.coTwitter's link wrapper.
Your task: read the problem above, then write what the system is, who uses it, the rough scope, and the headline non-functional concerns — in your own words. Submit for AI review when you're ready.
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Your understanding
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Senior-engineer feedback on what's strong, what's missing, and a calibrated score for this section.
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