AIML - Senior Full Stack Engineer, Siri Response Platform Engineering, Siri Information and Intelligence

Apple

Given an integer n, return the count of all numbers with unique digits, x, where 0 <= x < 10^n. For example: Input: n = 2 Output: 91 Explanation: The answer should be the total numbers in the range of 0 <= x < 100, excluding 11,22,33,44,55,66,77,88,99 Input: n = 0 Output: 1

Apple

Let's talk about semaphores. Could you please explain what semaphores are, and how they are used in operating systems or concurrent programming? Provide examples of situations where semaphores are useful for controlling access to shared resources. Explain the difference between binary and counting semaphores. Furthermore, can you discuss potential problems that can arise when using semaphores, such as deadlocks or starvation, and how these problems can be addressed? For instance, consider a scenario where multiple threads need to access a database connection pool. How can semaphores be employed to manage access to the limited number of connections in the pool, preventing overuse and ensuring fair allocation among threads?

Apple

Let's say a developer doesn't agree that a reported bug is actually a bug. How would you handle this situation? Be specific. For example, imagine you're a QA engineer, and you find that a button on a webpage is slightly misaligned in a specific browser. You log this as a bug, but the front-end developer says it's 'within acceptable tolerances' and refuses to fix it. Or, perhaps a back-end developer claims that a specific edge-case error is so rare it's not worth the effort to address, even though you believe it violates the product's stated reliability goals. What steps would you take to resolve the disagreement while maintaining a positive working relationship and ensuring product quality? Consider the different approaches you could take based on the severity and impact of the potential bug.