FAQs & Common Use Cases: Overview
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FAQs & Common Use Cases: Overview
Introduction
Algorithms are not just academic exercises; they are the tools we use to solve real-world engineering problems. This section provides a strategic overview of how to map complex requirements to the right algorithmic patterns.
Typical Business Scenarios
- “We need a leaderboard.” -> See Sorting & TopK (Chapter 3).
- “Our database is slow on text search.” -> See Inverted Index (Chapter 2.1).
- “We have millions of duplicate images.” -> See MinHash & LSH (Chapter 2.8).
- “How do we prevent API abuse?” -> See Rate Limiting (Chapter 5.5).
- “Which server should handle this request?” -> See Consistent Hashing (Chapter 4.3).
Selection Cheat Sheet (The Quick Map)
| Requirement | Best Pattern | Why? |
|---|---|---|
| Membership Check | Bloom Filter | Saves 90%+ RAM vs Hash Set. |
| Shortest Path | Dijkstra | Guaranteed optimal route. |
| Sub-second Search | Inverted Index | Bypasses linear scan. |
| Approx. Count | HyperLogLog | Counts billions in 1.5KB. |
| Trend Detection | Count-Min Sketch | Finds heavy hitters in streams. |
The Engineering Mindset
“An engineer’s job is not to implement the perfect algorithm, but to choose the one with the right trade-offs for the current scale, budget, and accuracy requirements.”