SDE 3 at Walmart

How it went

What they would tell you

How to prepare

Round by round

1. 1

   Technical Screening90 min

   The phone screen started with a straight dive into problem-solving. The interviewer was mainly interested in how I approach algorithms and whether I could write clean, efficient code under time pressure. We kicked things off with “Find All Anagrams in a String”. I used hashmaps and a sliding window to tackle it efficiently. After that, I was asked a streaming-based problem: “Find the Kth Highest Frequency Character in a Stream”, which tested my understanding of heaps and real-time frequency tracking. The last one was a classic: “Trapping Rain Water”. I implemented the two-pointer approach and walked through all the edge cases. Overall, it was a solid technical round focused on clarity, optimization, and how well I could think on my feet.

   • Trapping Rainwater
   • Find All Anagrams in a String
   • Find the Kth Highest Frequency Character in a Stream
2. 2

   Low-Level Design(System Design + Java Fundamentals)60 min

   This round really tested my low-level design and object-oriented thinking. The interviewer asked me to design a Role-Based Access Control (RBAC) system. Basically, I had to figure out how users, roles, and permissions would interact and how to structure that in a clean, scalable way. We then shifted into core Java concepts, where topics like garbage collection and multithreading came up. I explained how Java manages memory under the hood and how I’d approach handling concurrent tasks safely and efficiently. What worked in my favor was that I kept the design simple but well-structured, and I tied everything back to real-world applications. The interviewer specifically liked how I connected design patterns with practical scenarios.

3. 3

   Hiring Manager Round60 min

   This round felt like a mix of both tech and personality check. The hiring manager wasn’t just interested in what I had built, he wanted to know why I made certain choices and how I operate under pressure. We started with system design. I walked him through one of my past projects where I had used a microservices-based architecture. He asked why I chose MySQL over NoSQL, and I explained the data relationships and consistency needs that made SQL a better fit. We also discussed how the system handled load, ensured fault tolerance, and stayed highly available. Then came the behavioral part. He asked questions like “What’s a strength you're proud of?” or “Tell me about a time you had to make a decision with incomplete data.” I shared real examples, like resolving a production issue during crunch time with limited info and still making the right call. What worked for me was clear communication, I didn’t just throw jargon around. I told stories from my experience, and that made the conversation engaging and real.

   Tip: Be prepared to talk about your projects in-depth and explain why you made certain technical decisions.

4. 4

   HR Round60 min

   The final round was a relaxed conversation with the HR team, more about getting to know each other than grilling on technical stuff. They wanted to see if I’d be a good fit at Walmart, not just in terms of skills, but values and long-term vision. One of the first questions was, “Why Walmart?” I talked about how I admire the way Walmart is transforming retail through tech, especially at such a huge scale. It aligns with my interest in solving problems that impact millions. They also asked why I was considering a switch. I explained that while I was grateful for my current role, I was looking for a place where I could work on more scalable, impactful systems, something I believe Walmart offers. Compensation came up too. I was honest about my expectations and also open to understanding how Walmart structures their benefits and career progression. What worked in my favor was being transparent and showing that I’d done my homework on Walmart’s culture. The HR seemed to appreciate that I wasn’t just looking for a job, but the right place to grow.

What came up