Machine Learning Software Engineer L4/L5

Netflix

Write a function that validates if a given string is a valid representation of an integer. The function should handle positive, negative, and zero values. It should also account for leading/trailing spaces, but return false if there are any non-numeric characters other than a single leading '+' or '-' sign. Details: The input is a string. The output is a boolean: true if the string represents a valid integer, false otherwise. A valid integer string can start with an optional '+' or '-' sign. The rest of the string must contain only digits. Leading and trailing whitespace should be ignored. The string must not contain any other non-numeric characters. Examples: +123 should return true -456 should return true 0 should return true +007 should return true abc should return false 12.3 should return false 1a should return false should return false ++12 should return false --12 should return false 12+ should return false 12- should return false Considerations: Handle empty strings gracefully. Be mindful of potential integer overflow issues (although the function does not need to explicitly check for it). Focus on validating the format of the string. Ensure your solution efficiently handles various edge cases and invalid inputs. Your function should demonstrate clear, concise, and well-documented code.

Netflix

Let's discuss architecture and data modeling. Consider you're designing a system for a popular online bookstore. This bookstore needs to manage a vast catalog of books, track customer orders, and provide personalized recommendations. Walk me through your approach to designing the system's architecture and data model, keeping in mind scalability, performance, and maintainability. Be specific by considering these points: Microservices vs. Monolith: Would you opt for a microservices architecture or a monolithic architecture? Explain your reasoning, considering the bookstore's scale and potential future features. Data Storage: What types of databases would you use (e.g., relational, NoSQL)? Justify your choices for different parts of the system (e.g., catalog, orders, user profiles). Data Model: Describe the key entities (e.g., books, authors, customers, orders) and their relationships. Provide a simplified schema for these entities, highlighting essential attributes and data types. How would you handle relationships like a book having multiple authors or a customer placing multiple orders? Scalability: How would you design the system to handle a massive increase in traffic and data volume during peak seasons (e.g., holidays)? Consider aspects like load balancing, caching, and database sharding. Search Functionality: How would you implement the search functionality to allow users to quickly find books based on title, author, ISBN, or keywords? Consider indexing strategies and search algorithms. Recommendation Engine: Briefly outline how you would design a recommendation engine to suggest relevant books to users based on their browsing history, purchase history, and ratings. What data would you need to collect and how would you analyze it? Data Consistency: How would you ensure data consistency across different microservices and databases, especially when dealing with transactions like placing an order or updating inventory levels?

Netflix

Could you elaborate on some challenges you've encountered while working with Java and Scala?