Research Scientist L4/L5, Algorithms Engineering

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 say you have a complex e-commerce system composed of several subsystems: a user authentication service, a product catalog, a shopping cart, an order processing module, and a payment gateway. Each of these subsystems interacts with others to provide the complete shopping experience. How would you approach testing this entire system to ensure it functions correctly, is reliable, and meets performance expectations? Please describe the types of tests you would perform, the tools you might use, and how you would handle potential challenges like coordinating testing across multiple teams or simulating real-world user traffic.

Netflix

Let's delve into your past projects and experiences. I am interested in understanding how you approach problem-solving in real-world scenarios. Could you walk me through a particularly challenging project you've worked on, outlining the initial problem, the steps you took to address it, and the final outcome? What obstacles did you encounter, and how did you overcome them? Furthermore, what specific technologies or methodologies did you employ, and why were they chosen? For example, perhaps you worked on a project to optimize a database query that was causing performance bottlenecks. What steps did you take to identify the root cause of the bottleneck? Did you use any specific profiling tools or techniques? How did you determine the best approach to optimize the query, and what were the trade-offs involved? What was the measurable impact of your optimization efforts on the overall system performance? Alternatively, consider a project where you were tasked with migrating a legacy application to a new platform. What were the key challenges involved in this migration? How did you ensure data integrity and minimal downtime during the transition? What strategies did you use to manage the complexities of the migration process, and how did you collaborate with other team members to achieve a successful outcome? Finally, reflect on a time when you had to learn a new technology or skill quickly to contribute to a project. What strategies did you employ to accelerate your learning process? How did you apply your newfound knowledge to solve real-world problems within the project, and what lessons did you learn from this experience?