Amazon | Phone Screen | SDE 2

Anonymous User

1557

Recently appeared for a phone screen for SDE-2 position (Seattle, USA).

15 minutes: background introduction and LP question:
Question was on Leadership Principle INSIST ON THE HIGHEST STANDARDS:
Tell me about a time when you had to make a decision between reducing code quality standards to meet the tight deadline for delivery.
40 minutes: Coding Question:

Implement how the following use case can be optimized.
A program running on a mobile device with limited memory and computing power. It requires to access a certain set of resources from the server, once per time. 
A simplified workflow could be: 

Request resource A from server -> processed  
Request resource A from server -> processed  
Request resource B from server -> processed  
Request resource A from server -> processed  
Request resource B from server -> processed  
Request resource B from server -> processed  
Request resource B from server -> processed  
Request resource A from server -> processed  
Request resource C from server -> processed  
Request resource A from server -> processed  
Request resource C from server -> processed 
Request resource D from server -> processed  

If a resource is recently used, it will be very like to be accessed again. However, requesting resources from the server is an expensive operation for the backend service.

Solution:

The condition of being recently used and expensive server operations hint toward using an LRU Cache: 
Explained the reasoning and started to implement it after explanation was accepted. 
Refer for the implementation: https://leetcode.com/problems/lru-cache/

5 minutes: Q&A

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