Software Development Engineer

Amazon

Given a graph represented as an adjacency list, write a function to perform a Depth-First Search (DFS) traversal starting from a given node. The function should print each visited node. Also, provide an example graph and demonstrate how your function would traverse it. Explain the time and space complexity of your solution. For example, consider the following graph: { 0: [1, 2], 1: [2], 2: [0, 3], 3: [3] } If we start the DFS traversal from node 2, the expected output would be: 2, 0, 1, 3 (or another valid DFS traversal order). Your function should: Take the graph (adjacency list) and a starting node as input. Implement DFS traversal. Print each visited node. Correctly handle cycles to avoid infinite loops. Analyze and state the time and space complexity of your implementation.

Amazon

Elevator System Design Design an elevator system for a 20-story building. Consider the following: Number of Elevators: How many elevators would you recommend, and why? Elevator Capacity: What should be the capacity (in terms of weight and number of people) of each elevator? Algorithm for Request Handling: Describe an algorithm for efficiently handling elevator requests, considering factors like minimizing wait times and energy consumption. Example: Should the elevator always go to the closest floor first, or should it consider the direction of travel? Edge Cases and Error Handling: How would you handle edge cases such as: Elevator malfunction? Power outage? Overweight elevator? Simultaneous requests from multiple floors? Optimization: How can you optimize the system for peak hours (e.g., morning rush hour, lunch break)? Consider strategies like: Designating specific elevators for up/down travel during peak times. Implementing a learning system that adapts to usage patterns. User Interface: Describe the user interface (both inside the elevator and on each floor) and how it provides feedback to users. Scalability: How would the design change for a 50-story or 100-story building? What are the limitations of your current design? Explain your design choices and justify them with appropriate reasoning. Focus on creating a robust, efficient, and user-friendly elevator system.

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.