Software Engineer (L5) - ML - Studio & Creative Production Data Engineering

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

Design a Distributed Service Let's design a distributed service that can handle a large volume of requests while maintaining high availability and low latency. Consider a URL shortening service like TinyURL as an example. Specific Requirements: Functionality: The service should be able to: Accept a long URL and generate a unique short URL. Redirect users from the short URL to the original long URL. Scale: The service should be able to handle millions of URL shortening and redirection requests per day. Availability: The service should be highly available, with minimal downtime. Latency: The redirection from the short URL to the long URL should be as fast as possible. Storage: The service should efficiently store the mapping between short URLs and long URLs. Consider the Following Aspects in Your Design: Data Model:** How will you store the mapping between short and long URLs? What database technology will you use, and why? Algorithm for Short URL Generation:** How will you generate unique short URLs? How do you avoid collisions? System Architecture:** How will you distribute the load across multiple servers? What components will you use (e.g., load balancers, caches, databases)? Caching:** Where and how will you implement caching to improve performance? Fault Tolerance:** How will you ensure that the service remains available even if some servers fail? Monitoring and Alerting:** How will you monitor the health of the service and alert operators to potential problems? Walk me through your design, explaining the choices you make and the trade-offs involved. Be prepared to discuss alternatives and justify your decisions. For instance, why would you choose a relational database like MySQL over a NoSQL database like Cassandra, or vice versa? How would your design change if you needed to support custom short URLs?

Netflix

Tell me about a time you went above and beyond what was expected of you.