Dunnhumby Data Science Engineer Interview Questions, Process, and Tips

Basic ds algo round with questions asked around arrays strings

Q1. Minimum in Rotated Sorted array
Ans. 
Find the minimum element in a rotated sorted array.
• Perform binary search to find the pivot point where the array is rotated.

• Compare the element at pivot point to the first element to determine which half to search for the minimum.

• Continue binary search in the appropriate half to find the minimum element.
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Q2. API and DB Schema for Instagram based application.
Ans. 
API for Instagram application to interact with user data and DB schema to store user information and posts.
• API endpoints for user authentication, posting photos, liking photos, following users, etc.

• DB schema with tables for users, posts, comments, likes, followers, etc.

• Example API endpoint: /users/{userId}/posts to retrieve all posts by a specific user.

• Example DB schema: Users table with columns for username, email, pr
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Q1. Resume introspection, AWS, K8s
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Q1. Third party took the interview. Basics of programming and database were asked.
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Q1. Asked to build a small game. LLD round.
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Q1. What is a dirty read in a database?
Ans. 
A dirty read occurs when a transaction reads data that has been modified but not yet committed by another transaction.
• Dirty reads can lead to inconsistencies, as the data may change before the first transaction is committed.

• For example, if Transaction A updates a record but hasn't committed yet, and Transaction B reads that record, Transaction B sees uncommitted data.

• If Transaction A rolls back, Transaction B will have...read more
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Q2. What are design patterns?
Ans. 
Design patterns are reusable solutions to common software design problems, promoting best practices and improving code maintainability.
• Creational patterns (e.g., Singleton, Factory Method) manage object creation.

• Structural patterns (e.g., Adapter, Composite) deal with object composition.

• Behavioral patterns (e.g., Observer, Strategy) focus on communication between objects.

• Design patterns help in code reusability and sca
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