Senior Analytics Engineer (L5) - Product, Games

Netflix

Design and implement an LRU (Least Recently Used) cache. Your cache should support the following operations: get(key) - Gets the value (will always be positive) of the key if the key exists in the cache, otherwise returns -1. put(key, value) - Sets or inserts the value if the key is not already present. When the cache reaches its capacity, it should invalidate the least recently used item before inserting a new item. For the purpose of this question, when a new key is inserted, regard it as most recently used. The cache is initialized with a positive capacity. Example: LRUCache cache = new LRUCache(2); // capacity is 2 cache.put(1, 1); cache.put(2, 2); cache.get(1); // returns 1 cache.put(3, 3); // evicts key 2 cache.get(2); // returns -1 (not found) cache.put(4, 4); // evicts key 1 cache.get(1); // returns -1 (not found) cache.get(3); // returns 3 cache.get(4); // returns 4 Follow up: Could you do both operations in O(1) time complexity?

Netflix

Let's design an A/B test to re-engage inactive users of a mobile fitness app. Assume that users are considered inactive if they haven't used the app for 30 days. Our goal is to increase the number of users who return and actively use the app. Consider the following when designing your A/B test: Control Group: This group receives no intervention. We'll use this as our baseline to measure against. Treatment Group A: Push Notification with Personalized Workout Recommendations: Users in this group receive a push notification that includes workout recommendations tailored to their past activity and fitness goals (e.g., Ready for your next challenge? Try this 30-minute HIIT workout based on your past activity!). Treatment Group B: In-App Discount on Premium Features: Users in this group receive a notification when they open the app offering a discounted rate on the app's premium features, such as personalized training plans or access to exclusive content (e.g., Welcome back! Enjoy 50% off a premium training plan this week only!). For this A/B test design, specify: The hypothesis for each treatment group. The target metric(s) you would track to measure success, and how you would measure them. The segmentation you might consider when analyzing results (e.g. by workout type, fitness level, demographics). The duration of the A/B test and the sample size needed for statistical significance. Explain your reasoning. The potential risks and how you would mitigate them.

Netflix

Tell me about the most challenging product you've ever worked on. To fully explain the challenges, please address the following points: Describe the product: What was its purpose? Who was the target audience? What key features did it have? Explain the challenges: What specific technical or non-technical hurdles did you face during its development or maintenance? For example, did you struggle with scalability, performance, security, ambiguous requirements, tight deadlines, or limited resources? Be specific. Discuss your role: What were your responsibilities within the team? How did your skills and experience contribute to overcoming these challenges? Explain the solutions: What strategies or techniques did you employ to address these challenges? Did you have to learn new technologies, implement innovative solutions, or collaborate with other teams to succeed? Provide concrete examples. Describe the outcome: What was the result of your efforts? Did you successfully overcome the challenges? What impact did the product have on the users or the business? What lessons did you learn from this experience? For instance, imagine you were developing a real-time data analytics platform for a financial institution. A significant challenge was processing and analyzing massive volumes of data with low latency. You might discuss how you implemented distributed computing techniques, optimized database queries, and worked with data scientists to develop efficient algorithms. Or perhaps you were building a mobile app for a healthcare provider, and you struggled with ensuring patient data privacy and security. You could explain how you implemented end-to-end encryption, followed strict security protocols, and conducted thorough security audits. Or maybe you were tasked with modernizing a legacy system, and you encountered compatibility issues and resistance to change. You could describe how you carefully planned the migration process, communicated the benefits of the new system to stakeholders, and provided training to users.