System Development Engineer, IOTA, Project Kuiper

Amazon

Given a binary tree, find the lowest common ancestor (LCA) of two given nodes in the tree. According to the definition of LCA on Wikipedia: “The lowest common ancestor is defined between two nodes p and q as the lowest node in T that has both p and q as descendants (where we allow a node to be a descendant of itself). For example: If the tree is [3,5,1,6,2,0,8,null,null,7,4], p = 5, q = 1, then the expected output is 3, because the LCA of nodes 5 and 1 is 3. If the tree is [3,5,1,6,2,0,8,null,null,7,4], p = 5, q = 4, then the expected output is 5, because the LCA of nodes 5 and 4 is 5, since a node can be a descendant of itself according to the LCA definition. If the tree is [1,2], p = 1, q = 2, then the expected output is 1. Consider these constraints: The number of nodes in the tree is in the range [2, 10^5]. -10^9 <= Node.val <= 10^9 All Node.val are unique. p != q p and q will exist in the tree.

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

Why do you want to work at Amazon? To provide a comprehensive answer, consider the following aspects: Amazon's Mission and Values: How do Amazon's core values, such as customer obsession, innovation, bias for action, and ownership, resonate with your personal and professional values? Provide specific examples of how you've demonstrated similar values in your previous experiences. For instance, can you describe a situation where you went above and beyond to satisfy a customer, or when you took initiative to implement a novel solution to a challenging problem? Amazon's Culture of Innovation: Amazon is renowned for its innovative culture and willingness to experiment. How does this environment appeal to you? Are there any specific Amazon products, services, or initiatives that you find particularly inspiring or exciting? Perhaps you're impressed by Amazon Web Services (AWS), Amazon's foray into artificial intelligence with Alexa, or their advancements in logistics and delivery. Explain why these innovations capture your interest and how you believe you could contribute to future innovation at Amazon. Growth and Learning Opportunities: Amazon offers a wide range of opportunities for professional growth and development. What specific roles or career paths within Amazon are you interested in exploring, and why? Have you researched Amazon's internal training programs or mentorship opportunities? Discuss how you envision leveraging these resources to expand your skillset and advance your career within the company. For example, are you interested in moving into a leadership role, specializing in a particular technology, or working on a global scale? Your Skills and Experience: How do your skills and experience align with Amazon's needs and priorities? Identify specific projects or accomplishments from your past that demonstrate your ability to succeed in a fast-paced, demanding environment. Highlight any experience you have with technologies or methodologies that are relevant to Amazon's business, such as cloud computing, data analysis, machine learning, or agile development. Be prepared to discuss how your unique skills and experiences can contribute to Amazon's continued success. Can you quantify your accomplishments with metrics? Company Impact: What excites you about the potential to contribute to Amazon's impact on customers and the world? Consider how Amazon's products and services have transformed industries and improved people's lives. Are you drawn to the scale and scope of Amazon's operations, or the opportunity to work on projects that have a global reach? Express your enthusiasm for being part of a company that is constantly pushing boundaries and shaping the future.