Senior Software Engineer, Machine Learning, Google Ads

Google

Given n pairs of parentheses, what is the total number of different, valid combinations of those parenthesis? For example: For n = 1, the only valid combination is (), so the answer is 1. For n = 2, the valid combinations are ()() and (()), so the answer is 2. For n = 3, the valid combinations are ((())), (()()), (())(), ()(()), and ()()(), so the answer is 5. Calculate the number of valid parenthesis combinations for a given n. Explain the formula or method used to arrive at the answer. What is the underlying mathematical concept at play here, and how does it ensure that we only count valid combinations, avoiding invalid ones such as )()(? Detail the relationship between this problem and Catalan numbers, and discuss how this relationship can be utilized to efficiently compute the number of valid combinations, even for relatively large values of n.

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API Design Question: E-commerce Product Catalog Let's design a simplified API for an e-commerce product catalog. Imagine you're building the backend for a website like Amazon or Etsy, focusing specifically on how products are stored and retrieved. This API will allow client applications (like web browsers or mobile apps) to browse, search, and view product details. Define the Core Entities: What are the essential attributes of a Product? Consider attributes like product_id, name, description, price, category, image_url, and inventory_count. Are there other attributes you would include? Justify your choices. Design the API Endpoints: Propose the main API endpoints for interacting with the product catalog. Focus on the following functionalities. Provide example requests and responses (in JSON format) for each endpoint: Retrieve a product by ID: (/products/{product_id}) Search for products: (/products?keyword=example&category=example) List products by category: (/categories/{category_name}/products) Considerations: How would you handle pagination for large product lists? How would you implement filtering and sorting options in the search endpoint? (e.g., filter by price range, sort by popularity). How would you handle different image sizes and formats? Example Scenario: A user searches for red shoes on the website. Describe how the API would be used to fulfill this request, including the specific endpoint called, the parameters passed, and the format of the expected response.

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Describe a time you faced a tough technical problem. What made it so difficult, and how did you approach solving it? What resources did you consult, and what was the final outcome? What did you learn from this experience, and how has it shaped your problem-solving skills since then? For example, perhaps you were tasked with optimizing a slow-running query in a large database. The initial attempts to improve performance, such as adding indexes, didn't yield the desired results. You then had to dive deep into the query execution plan, identify bottlenecks, and rewrite the query using more efficient techniques, like leveraging window functions or temporary tables. You could also describe the challenges faced while integrating a new feature into a legacy system with poorly documented code. You might have had to reverse engineer parts of the system, deal with unexpected dependencies, and carefully test the integration to avoid breaking existing functionality. Elaborate on the specific tools and methodologies you employed during these challenges, such as debuggers, profilers, or version control systems. Also, explain how you collaborated with team members or sought assistance from external resources like online forums or documentation to overcome the obstacles.