Software Development Engineer, PBI Supply Chain Innovation

Amazon

Explain the concept of a circular linked list. Describe its advantages and disadvantages compared to a singly linked list. Provide an example of a scenario where a circular linked list would be a suitable data structure, and write code snippets in Python or Java to demonstrate how to insert a node into a circular linked list and traverse the list. Explain how to detect if a circular linked list has a loop.

Amazon

Let's design a turnstile. A turnstile is a type of gate which allows one person to pass at a time. Consider a turnstile at a subway station. There are two panels that rotate to allow a single person passage. The turnstile has two states, Locked and Unlocked, and the customer can either Push the turnstile or Insert a token/card. Here is the state transition table: | Event | Current State | Action | Next State | | :----- | :------------ | :------------- | :--------- | | Push | Locked | | Locked | | Token | Locked | Unlock | Unlocked | | Push | Unlocked | Pass through | Locked | | Token | Unlocked | (discarded) | Unlocked | Requirements: Model the state and behavior of a simple turnstile. Implement two methods: insert_token() push() Consider edge cases and error handling. What happens if someone tries to push without inserting a token? What happens if the system malfunctions? Example: turnstile = Turnstile() print(turnstile.state) # Output: Locked turnstile.push() print(turnstile.state) # Output: Locked turnstile.insert_token() print(turnstile.state) # Output: Unlocked turnstile.push() print(turnstile.state) # Output: Locked How would you approach this design and implementation, keeping in mind scalability, maintainability, and potential future extensions such as different types of tokens or remote unlocking?

Amazon

Tell me about a project that you're most proud of. To help me understand the scope and impact, please provide specific details about the project, including: The problem: What challenge were you trying to solve, and why was it important? Your role: What specific responsibilities did you have on the project? What were your key contributions? The technical details: What technologies, tools, or techniques did you use? For example, did you work with a specific programming language, framework, or database? The outcome: What were the results of the project? Did you meet the initial goals? Did you encounter any unexpected benefits or challenges? What did you learn?: Looking back, what would you do differently? What skills or knowledge did you gain from the experience? Did you face any setbacks, and how did you overcome them? For instance, if you worked on a project to improve the performance of a web application, you might discuss the specific performance bottlenecks you identified, the optimization techniques you implemented (e.g., caching, code optimization), and the resulting improvement in response time or throughput. Or, if you designed a new feature for a mobile app, you could describe the user research you conducted, the design process you followed, and the metrics you used to measure the feature's success. Be prepared to discuss technical challenges you faced and how you addressed them.