GK Question

technology hard mcq

Which data structure is most efficient for implementing a cache with LRU (Least Recently Used) eviction policy?

  1. Array
  2. Linked List
  3. Hash Map + Doubly Linked List
  4. Stack

Answer: Hash Map + Doubly Linked List

LRU cache requires O(1) access and O(1) reorder on access. Hash map provides O(1) key lookup; doubly linked list maintains usage order with O(1) move-to-front. Combined, they achieve O(1) get/put operations. Classic system design question for SSC JE and banking IT exams.

Topic Data Structures
Exam Relevance SSC JE, Banking IT, UPSC
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