Software Development Engineer, Last Mile Routing and Planning Team

Amazon

You are given a string moves of length n consisting only of characters 'L', 'R', and '_'. The string represents your movement on a number line starting from the origin 0. In the ith move, you can choose one of the following directions: move to the left if moves[i] = 'L' or moves[i] = '_' move to the right if moves[i] = 'R' or moves[i] = '_' Return the *distance from the origin* of the *furthest* point you can get to after n moves. Example 1: Input: moves = L_RL__R Output: 3 Explanation: The furthest point we can reach from the origin 0 is point -3 through the following sequence of moves LLRLLLR. Example 2: Input: moves = R__LL Output: 5 Explanation: The furthest point we can reach from the origin 0 is point -5 through the following sequence of moves LRLLLLL. Example 3: Input: moves = _ Output: 7 Explanation: The furthest point we can reach from the origin 0 is point 7 through the following sequence of moves RRRRRRR.

Amazon

Let's design a Twitter-like service. Consider the following: Core Functionality: How would you implement the ability for users to post tweets, follow other users, and view a timeline of tweets from the users they follow? Data Model: What database schema would you use to store tweets, user information, and follower relationships? Consider scalability and efficiency for reads and writes. Scalability: How would you handle a large number of users and tweets? Discuss strategies for sharding, caching, and load balancing. Real-time Updates: How would you ensure that users see new tweets in their timeline in near real-time? Consider using technologies like WebSockets or Server-Sent Events. Search: How would you implement a search feature that allows users to find tweets containing specific keywords or hashtags? Think about indexing strategies and search algorithms. Rate Limiting: How would you prevent abuse and ensure fair usage of the service? Describe your approach to rate limiting API requests. Example Scenario: Imagine a user, Alice, follows 1,000 other users, including Bob. Bob posts a tweet. Explain how that tweet would propagate to Alice's timeline, considering potential performance bottlenecks. Technology Stack: What technologies (programming languages, frameworks, databases, etc.) would you choose and why?

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.