Distributed Systems Engineer (L4) - Data Platform

Netflix

Given a string containing digits from 2-9 inclusive, return all possible letter combinations that the number could represent. Return the answer in any order. A mapping of digit to letters (just like on the telephone buttons) is given below. Note that 1 does not map to any letters. 2: abc 3: def 4: ghi 5: jkl 6: mno 7: pqrs 8: tuv 9: wxyz Example 1: Input: digits = 23 Output: [ad,ae,af,bd,be,bf,cd,ce,cf] Example 2: Input: digits = Output: [] Example 3: Input: digits = 2 Output: [a,b,c]

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

Let's discuss your previous projects in detail. I'd like to understand your role, the challenges you faced, and the solutions you implemented. To help me understand the scope of your work, please walk me through a project where you significantly contributed to the success of the team or the company. Elaborate on the technologies you used, the architecture you designed (if applicable), and the methodologies you followed (e.g., Agile, Waterfall). Be prepared to discuss specific technical decisions you made and the trade-offs you considered. For instance, can you describe a situation where you had to choose between performance and scalability, and how you arrived at your decision? Or, tell me about a time when you had to debug a particularly complex issue in a project? What steps did you take to identify the root cause, and how did you go about fixing it? I am also interested in hearing about any failures or setbacks you experienced during a project. What did you learn from those experiences, and how did you apply those lessons in subsequent projects? Finally, can you quantify the impact of your contributions to the project in terms of metrics such as improved performance, reduced costs, or increased user engagement?