Data Scientist

Oracle

Let's explore some common data structures and algorithms. I'd like you to describe the following: Arrays: Explain what an array is and how it stores data. What are the advantages and disadvantages of using arrays? Provide an example of how you would use an array in a real-world scenario. For instance, how could you use an array to store a list of student names or inventory items? Linked Lists: What is a linked list, and how does it differ from an array? Describe the different types of linked lists (singly, doubly, circular). Walk me through the process of inserting a node into a singly linked list. What are the time complexities of insertion and deletion in a linked list? Stacks and Queues: Explain the concepts of stacks and queues. What are the key differences between them? (LIFO vs FIFO). Give an example of a situation where you would prefer to use a stack over a queue, and vice versa. How could you implement a queue using two stacks? Trees: Describe what a tree data structure is. What are the different types of trees (binary tree, binary search tree, etc.)? Explain the properties of a binary search tree. How does it enable efficient searching? How would you traverse a binary tree (in-order, pre-order, post-order)? Provide examples. Sorting Algorithms: Explain the concept of sorting algorithms. Describe the following sorting algorithms: Bubble Sort, Insertion Sort, Merge Sort, and Quick Sort. What are the time complexities of each of these sorting algorithms in the best, average, and worst-case scenarios? Which sorting algorithm would you choose for a nearly sorted array, and why? Searching Algorithms: Describe the difference between linear search and binary search. When is binary search applicable, and what are its advantages? What is the time complexity of linear search and binary search? For each of these, please be prepared to discuss their real-world applications, time and space complexities, and trade-offs.

Oracle

Let's design a system for deleting all user data in a large-scale application. Consider the following requirements: Compliance: The system must adhere to data privacy regulations (e.g., GDPR, CCPA) regarding the right to be forgotten. This means all personal data must be permanently and irrevocably deleted. Data Scope: User data is distributed across various databases (e.g., relational, NoSQL), object storage, and potentially third-party services. Examples include: User profiles in a relational database (name, email, address). User-generated content (photos, videos) in object storage. User activity logs in a NoSQL database. User data cached in a Redis cluster. User accounts on integrated third-party services (e.g., payment processors, social media platforms). Performance: The deletion process should be efficient and not significantly impact the performance of other system operations. Consider the impact on databases and other services during peak hours. Consistency: The system must ensure data consistency. For example, if a user has dependencies on other data (e.g., a user is an administrator of a group), these dependencies must be handled correctly (e.g., reassigning ownership, deleting dependent data). Auditability: All deletion requests and actions must be logged for auditing and compliance purposes. The logs should record who requested the deletion, when it was requested, what data was deleted, and the outcome of the deletion process. Error Handling: The system should gracefully handle errors and retries. If a deletion fails in one component, it should be retried or rolled back appropriately, and alerts should be generated. Scalability: The system must be able to handle a large number of deletion requests concurrently. Data Minimization: Before initiating the deletion process, verify if data minimization techniques can be applied instead of complete deletion, such as anonymization or pseudonymization, especially for datasets needed for analytical purposes. Given these requirements, how would you design a system to handle user data deletion requests? Discuss the architecture, components, data flow, and any trade-offs you would consider.

Oracle

Okay, let's imagine we're at a career fair, and you have about two minutes to introduce yourself to a recruiter. Keeping that timeframe in mind, could you provide a concise overview of your background, skills, and career aspirations? Think of it as your elevator pitch. For example, you might highlight your key accomplishments from previous roles, discuss your proficiency in specific programming languages or technologies relevant to the target position, and briefly touch upon your career goals and what you're hoping to achieve in your next role. What makes you a great candidate?