Data Scientist (L5) - Ads (Experimentation)

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

Design a Distributed Service Let's design a distributed service that can handle a large volume of requests while maintaining high availability and low latency. Consider a URL shortening service like TinyURL as an example. Specific Requirements: Functionality: The service should be able to: Accept a long URL and generate a unique short URL. Redirect users from the short URL to the original long URL. Scale: The service should be able to handle millions of URL shortening and redirection requests per day. Availability: The service should be highly available, with minimal downtime. Latency: The redirection from the short URL to the long URL should be as fast as possible. Storage: The service should efficiently store the mapping between short URLs and long URLs. Consider the Following Aspects in Your Design: Data Model:** How will you store the mapping between short and long URLs? What database technology will you use, and why? Algorithm for Short URL Generation:** How will you generate unique short URLs? How do you avoid collisions? System Architecture:** How will you distribute the load across multiple servers? What components will you use (e.g., load balancers, caches, databases)? Caching:** Where and how will you implement caching to improve performance? Fault Tolerance:** How will you ensure that the service remains available even if some servers fail? Monitoring and Alerting:** How will you monitor the health of the service and alert operators to potential problems? Walk me through your design, explaining the choices you make and the trade-offs involved. Be prepared to discuss alternatives and justify your decisions. For instance, why would you choose a relational database like MySQL over a NoSQL database like Cassandra, or vice versa? How would your design change if you needed to support custom short URLs?

Netflix

Tell me about a time you faced a significant ethical dilemma. What made it difficult, and what was the outcome? Describe the situation in detail, explaining the context and the stakeholders involved. Explain your thought process as you evaluated the ethical considerations. What alternatives did you consider, and why did you choose the path you did? What was the result of your actions, and what did you learn from the experience? For example, perhaps you discovered a colleague was misrepresenting their work or claiming credit for someone else's contributions. Or maybe you identified a potential safety issue with a product or service that your company was preparing to launch. Discuss how you navigated the situation, ensuring that your actions aligned with your personal and professional values, while also considering the potential impact on your team, the company, and other stakeholders. Explain how you communicated your concerns and the steps you took to reach a resolution, reflecting on whether you would approach the situation differently in the future.