Software Engineering L5, Ads Creatives & Policy

Netflix

You are given the definition of a binary tree node: class Node: def init(self, val=0, left=None, right=None): self.val = val self.left = left self.right = right Write a function is_bst(root) that takes the root of a binary tree as input and returns True if the tree is a valid Binary Search Tree (BST), and False otherwise. Definition of a BST: The left subtree of a node contains only nodes with keys less than the node's key. The right subtree of a node contains only nodes with keys greater than the node's key. Both the left and right subtrees must also be binary search trees. Example 1: Input: root = [2,1,3] Output: true 2 / 1 3 Example 2: Input: root = [5,1,4,null,null,3,6] Output: false 5 / 1 4 / 3 6 Explanation: The root node's value is 5 but its right child's value is 4. Constraints: The number of nodes in the tree is in the range [1, 10000]. -10000 <= Node.val <= 10000 Your solution should handle edge cases such as an empty tree or a tree with only one node.

Netflix

High-Level Design for Zero-Downtime Live Production Systems Imagine you're tasked with designing a live production system that requires zero downtime during deployments and updates. This system handles a large volume of requests and is critical to the business. Let's consider a scenario: Scenario: You are building a service that provides real-time stock quotes to users. The service needs to be highly available and scalable to handle peak loads. Deployments must not interrupt the service, ensuring users always receive the latest data. Questions to address in your design: High-Level Architecture: Describe the overall architecture of the system. Include key components, their responsibilities, and how they interact. Deployment Strategy: Detail the deployment strategy you would use to achieve zero downtime. Explain the steps involved in deploying new versions of the service. Load Balancing: How would you distribute traffic across different instances of the service to ensure high availability and prevent overload? Monitoring and Rollback: What monitoring tools and metrics would you use to detect issues during deployment? Describe the rollback strategy in case of a failed deployment. Data Consistency: How would you ensure data consistency across different instances of the service during updates? Scaling: How would you scale the system horizontally to handle increased traffic? Explain each of these areas with consideration to both the design and the practical steps required for running such a system in live production. Consider specific technologies and tools where appropriate to illustrate your understanding. This question aims to assess your understanding of designing and operating highly available systems, your knowledge of deployment strategies, and your ability to handle real-world challenges in a production environment.

Netflix

Let's discuss your previous projects in detail. I'd like to understand your role, the challenges you faced, and the solutions you implemented. To help me understand the scope of your work, please walk me through a project where you significantly contributed to the success of the team or the company. Elaborate on the technologies you used, the architecture you designed (if applicable), and the methodologies you followed (e.g., Agile, Waterfall). Be prepared to discuss specific technical decisions you made and the trade-offs you considered. For instance, can you describe a situation where you had to choose between performance and scalability, and how you arrived at your decision? Or, tell me about a time when you had to debug a particularly complex issue in a project? What steps did you take to identify the root cause, and how did you go about fixing it? I am also interested in hearing about any failures or setbacks you experienced during a project. What did you learn from those experiences, and how did you apply those lessons in subsequent projects? Finally, can you quantify the impact of your contributions to the project in terms of metrics such as improved performance, reduced costs, or increased user engagement?