Education: B.Tech in Computer Science from an old NIT
Work Experience: SDE 2 at an investment bank (2.5 years of experience at the time of the interview)
I applied to Walmart through a referral, and after my resume was shortlisted, a recruiter reached out to me five days from the date of applying. The first round was then scheduled for the very next day.
Round 1 (DSA and Java):
There were two DSA questions in this round. One was https://leetcode.com/problems/task-scheduler-ii/description/ and the other was to implement pow(a, b) using Binary Exponentiation.
After that, there were questions on Java covering topics like boxing, ORM, Java Streams (finding the sum of squares of even numbers), Runnable and Callable interfaces, and thread states and a couple more questions on Concurrency and multi threading related to ExecutorService and CompletableFuture.
There were also a few questions based on my resume, including Reactive Programming and backpressure, along with some basic discussion on Kubernetes.
Round 2 (LLD):
The problem statement was to design an interface for submitting and managing workflows that can run tasks either sequentially or in parallel, with a provision for passing data between workflows. There was an in-depth discussion on the class diagram and design patterns, followed by coding a few interfaces, classes, and key methods.
This went on for about 40-45 minutes, after which the focus shifted to topics from my resume. Most of the questions from this point were on Kafka’s internals (log replication, leader election, durability, partitions, consumer groups) and its use cases.
Round 3 (Hiring Manager):
The discussion started with the tech stack used at my organization and an overview of the business problem we were solving. This was followed by a deep dive into a caching solution mentioned in my resume, covering general caching requirements and pseudo-code implementations for eviction policies like LRU, LFU, and FIFO. I was also asked how I would implement TTL in a cache.
There were a few follow-up questions on topics like CP subsystem, the CAP theorem, and managing a distributed cache across multiple pods using a consensus algorithm.
Towards the end, there were general and behavioral questions on handling bugs and production issues resolution, stakeholder and deadline management, and what keeps me motivated.
Round 4 (HR):
The discussion included usual HR questions like my strengths, a time when I dealt with a tough situation, and how I handle conflicts. After that, the HR explained the benefits and perks at Walmart and concluded by providing a verbal offer.
Overall the interviewers were understanding and interactive, and all four rounds were conducted with a gap of about two days between each.
I got the offer letter five days after receiving the verbal confirmation, which I accepted.
Offer details: https://leetcode.com/discuss/compensation/6492167/Walmart-or-Software-Engineer-3-or-Bengaluru