Software Engineer L4/L5, Model Serving Systems, Machine Learning Platform

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 delve into the Observer pattern. Imagine you're building a stock market application. You have a central Stock object that holds the current price. Multiple components, such as a PriceDisplay, a Graph, and an AlertSystem, need to update whenever the Stock price changes. Explain the Observer pattern: Describe the core components (Subject, Observer) and how they interact. Explain the benefits of using this pattern in scenarios like the stock market application. Design Implementation: Provide a simplified code implementation of the Observer pattern for this stock market scenario. Show how the Stock object (Subject) would manage its observers (PriceDisplay, Graph, AlertSystem) and how these observers would receive updates when the stock price changes. Focus on clarity and demonstrating the core concepts. Trade-offs: What are the potential drawbacks of using the Observer pattern, especially in a system with a large number of observers? How might you mitigate these issues (e.g., using weak references, asynchronous updates)? Alternatives: Are there alternative patterns or approaches you might consider instead of the Observer pattern for this type of scenario? What are the pros and cons of these alternatives compared to the Observer pattern? Real-world Examples: Besides a stock market application, can you describe other real-world examples where the Observer pattern is commonly used?

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.