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Design an Image Cache Library

HardCoding00:00
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Your question is Design an Image Cache Library. Take a moment with it on the right.

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Problem

Design an in-memory image cache library. The cache should support fast lookup by key, bounded memory usage, and automatic eviction when memory pressure increases. Explain how you would store entries, choose what to evict, and react to memory warnings or low-memory conditions.

What to Cover

  • Cache API and keying strategy
  • Eviction policy for hot vs cold images
  • Handling decoded images under memory pressure
  • Thread safety for concurrent reads and writes

Constraints

  • Memory budget is fixed and may shrink at runtime
  • Image entries vary widely in size
  • Lookups should remain fast under concurrent access
  • The cache should degrade gracefully instead of failing abruptly