Software Engineer III, Infrastructure, Google Ads

Google

Let's simulate a coding interview scenario. I'd like you to solve a problem and articulate your thought process as you go. Imagine you're given an array of integers. Your task is to write a function that finds the length of the longest strictly increasing subsequence in that array. A strictly increasing subsequence is a sequence of numbers from the array such that each number is greater than the previous one, and their original order in the array is maintained. For example, in the array [1, 3, 2, 4, 5], one possible increasing subsequence is [1, 2, 4, 5], and the longest increasing subsequence is [1, 2, 4, 5], which has a length of 4. Another possible increasing subsequence is [1, 3, 4, 5] which has length of 4. Your function should return 4 in this case. Another example is [10, 9, 2, 5, 3, 7, 101, 18]. The longest increasing subsequence is [2, 3, 7, 18], which has a length of 4. Your function should return 4. Can you describe your approach and then implement the function? Consider edge cases, like an empty array or an array with only one element. How would your approach handle those? What is the time and space complexity of your solution?

Google

Let's design a rate limiter for an API. The rate limiter should: Limit the number of requests a user can make to an API within a given time window. Support different rate limits for different users or API endpoints. For example, a free tier user might be limited to 10 requests per minute, while a premium user can make 100 requests per minute. Similarly, some API endpoints might have lower rate limits than others due to resource constraints. Be highly performant to avoid adding significant latency to API requests. Be scalable to handle a large number of users and API requests. Be reliable and prevent accidental overloads that could cause service disruptions. Describe the architecture, algorithms, and data structures you would use to implement such a rate limiter. Consider the following: How would you store the rate limit counters for each user or endpoint? What algorithm would you use to determine whether a request should be allowed or throttled? How would you handle distributed rate limiting across multiple servers? How would you ensure the rate limiter is resilient to failures? As an example, imagine a scenario where a social media platform wants to prevent users from spamming their API with excessive requests to post updates. The platform has millions of users and thousands of API endpoints. Some users pay for premium access with higher request limits. How would you design a robust and efficient rate limiter to handle this scale and these varying requirements?

Google

Okay, let's delve into your motivations. Why are you interested in working at this company specifically? I'm looking for more than just a generic answer about seeking a new job. I want to understand what resonates with you about our company's mission, values, and the specific role you're applying for. To give you some context, consider our commitment to innovation in the field of AI, particularly our recent work on developing more ethical and transparent algorithms. Or perhaps you're drawn to our collaborative work environment, where cross-functional teams work together to solve complex problems. Maybe you admire our company's dedication to social responsibility, like our initiatives to promote STEM education in underserved communities. When answering, please be specific and show that you've done your research. For instance, you could discuss a particular project that caught your attention, how your skills and experience align with the team's needs, or how you see yourself contributing to our company's long-term goals. Avoid vague statements like I'm a hard worker or I'm a team player without providing concrete examples. Instead, focus on demonstrating a genuine interest in our company and a clear understanding of how you can make a valuable contribution. To summarize, I want to know: What specifically attracts you to our company? How do your skills and experiences align with the requirements of this role and the company's goals? What unique contributions do you believe you can make to our team and our overall mission?