MSFT SDE2/ Senior Software engineer Interview experience
Summary
I interviewed for an SDE2/Senior Software Engineer role at Microsoft, facing rounds that included a challenging tree problem, a rate limiter implementation, a custom queue implementation, and a system design discussion. Despite a shaky performance in the first round, I am awaiting the outcome.
Full Experience
I had my interview experience for an SDE2/Senior Software Engineer position at Microsoft.
Round 1: Data Structures & Algorithms
The first round involved a tree problem where I was asked to point each node in a tree to its next node at the same level. This problem took me a considerable amount of time to finalize the logic, and while I coded most of it, I unfortunately missed adding a couple of lines for the recursion. I felt this was probably my worst round.
Round 2: Data Structures & Algorithms / System Design Lite
The second round focused on implementing a token-based rate limiter. I managed to get the logic right and successfully explained how this approach addresses the issues often seen with fixed-window rate limiters.
Round 3: Data Structures & Algorithms
In the third round, I was tasked with implementing a queue using a fixed-size array, utilizing head and tail pointers. I implemented both the enqueue and dequeue methods, and the interviewer seemed satisfied with my solution.
Round 4: System Design
The final round was a system design interview. The scenario involved customer data residing in Region A, but the user experience (UX) service operating in Region B. The user would make a call to the UX service to determine which region to contact to retrieve customer data. My proposed solution involved using HTTP redirects, leveraging Redis cache (discussing both instance and cluster considerations), handling customer information updates with Kafka, and minimizing costs by employing hot-warm instances of Redis.
Interview Questions (4)
Point Node to Next Same-Level Node in Tree
Given a binary tree, populate each next pointer to point to its next right node. If there is no next right node, the next pointer should be set to NULL. Initially, all next pointers are set to NULL. (Similar to LeetCode's 'Populating Next Right Pointers in Each Node' or similar level-order traversal problems).
Implement Token-Based Rate Limiter
Implement a token-based rate limiter. Discuss its design, advantages, and how it avoids common issues found in other rate limiting strategies like fixed window.
Implement Queue with Fixed-Size Array
Implement a queue data structure using a fixed-size array. The implementation should utilize head and tail pointers and include enqueue and dequeue methods.
System Design: Cross-Region Customer Data Access
Design a system where customer data resides in Region A, but the user experience (UX) service is deployed in Region B. Users interact with the UX service to retrieve their customer data. Outline the architecture to efficiently access customer data across regions, considering latency, consistency, and cost.