Architecture & LLD Preview
In-Memory Design Framework
How to approach in-memory design LLD problems — structure + policy + reclamation, and why one data structure never works alone.
Pair a lookup structure (hashmap, trie) with a second structure that captures order/time/rank (linked list, heap, timestamp log); reclaim expired or evicted state via a lazy check plus a background sweep, never a full scan.
Core Design Challenge
"Design an in-memory cache/limiter/store. Why does a single data structure never give you both O(1) lookup and O(1) ordering?"
What You'll Learn:
- ✦Understanding eviction policies (LRU, LFU, FIFO)
- ✦Designing O(1) time complexity maps and list structures
- ✦Thread-safety, mutex locking, and concurrent read/write access
- ✦Managing memory boundaries and cache expiration policies