LFU Cache Design | Dataford Interview Questions

Design and implement an LFU cache (LeetCode 460); at least implement get() and explain the approach.

Asked in the R2 Coding/HLD stage. Only 25-30 minutes remained after a 30-minute HLD discussion of a past project's database design tradeoffs.

Implement lfu_cache(capacity, operations). Each operation is ['put', key, value] or ['get', key]. Return the values from all get operations, using -1 for missing keys. When full, evict the least frequently used key. If frequencies tie, evict the most recently used tied key.

Constraints

0 <= capacity <= 10^5
1 <= len(operations) <= 10^5
Each operation is either ['get', key] or ['put', key, value]
Keys and values are integers

Function Signature

def lfu_cache(capacity, operations):

Your question is LFU Cache Design. Start with the requirements in the Question tab.

Run and submit as often as you like. When you're ready, talk me through your approach or go straight to the code.

Problem

Design and implement an LFU cache (LeetCode 460); at least implement get() and explain the approach.

Asked in the R2 Coding/HLD stage. Only 25-30 minutes remained after a 30-minute HLD discussion of a past project's database design tradeoffs.

Constraints

0 <= capacity <= 10^5
1 <= len(operations) <= 10^5
Each operation is either ['get', key] or ['put', key, value]
Keys and values are integers

Function Signature

def lfu_cache(capacity, operations):

Your question is LFU Cache Design. Start with the requirements in the Question tab.

Run and submit as often as you like. When you're ready, talk me through your approach or go straight to the code.