Staff Software Engineer, Google Cloud

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.

Google

Let's design a prototype for a system that answers questions based on financial documents. To make this concrete, imagine a user needs to quickly find information within a company's annual report (a PDF containing financial statements, management discussion, etc.). The user might ask questions like: What was the company's revenue for the last fiscal year? What were the primary risks identified by management? How did operating expenses change compared to the previous year? Describe your approach to building a prototype that can accurately and efficiently answer these types of questions. Consider aspects such as: Document ingestion and processing:** How would you load and pre-process the financial documents (e.g., PDF parsing, text extraction)? Information retrieval:** What techniques would you use to identify the relevant sections of the document that contain the answer? Question answering:** How would you extract the answer from the relevant text (e.g., using rule-based methods, machine learning models)? Data storage:** How would you store the information from the documents to allow for efficient querying? User interface:** How would the user interact with the system to ask questions and receive answers? Evaluation:** How would you evaluate the performance of your prototype?

Google

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.