B CareerByteCode
DSA Beginner 👋 CareerByteCode

Build an LRU Cache from Scratch

Implement a least-recently-used cache with O(1) get and put, the classic interview and systems building block.

Problem statement

You need a fixed-size cache that evicts the least recently used item when full, and both reads and writes must be O(1).

Why we need this realtime usecase

An LRU cache is the workhorse behind page caches, memoization, and hot-key stores; building one teaches the hash-map plus doubly-linked-list pattern.

When we need this realtime usecase

Use this whenever bounded memory must keep the most useful entries, and expect it in systems interviews.

Prerequisites for the lab

A language you know and comfort with hash maps and linked lists.

Step by step implementation 🔒
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Conclusion 🔒
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