Microsoft Senior Software Engineer Interview Experience — Painter's Partition Screen, Same-Day Two-Round Loop, Then the AA Round

I applied for a Senior Software Engineer opening through the careers portal. About a week later a recruiter phoned to set up a technical screen, and the screen itself took place a week after that. This was my first ever Microsoft interview, so I was thrilled and nervous in equal measure.

Technical Screen round
The screen was a single coding problem, labelled LeetCode easy. I didn't recognize it at first, but after a couple of read-throughs it clicked that it was basically the Painter's Partition problem, so I went with binary search. I hit a wall partway through, and I kept talking through my reasoning with the interviewer. A couple of hints later I had tightened up the solution and got it done.

Since this was my first time with Microsoft, I had read around online and noticed their process isn't like the Amazon or Google ones. So once the problem was done, I asked my interviewer how to prepare and where to put my effort. That turned out to be a real game changer. The interviewer wouldn't discuss the question itself, but gave me honest guidance about the process and what to focus on, and I'm passing it along in case it helps someone:

1. At the senior level, the coding round is frequently just a checkpoint on data structures and algorithms. A half-finished answer can still pass if your DSA strength shows in how you attack the problem, how you split it up, and whatever partial code you reach. They are looking for conceptual understanding, efficient coding, and the ability to optimize.
2. When it comes to senior roles, the hiring call leans mostly on the HLD rounds. In order of weight: HLD+LLD>Coding

After that I shifted more of my prep time toward High-Level Design (HLD) and Low-Level Design (LLD), though as it happened I never got an LLD round. About 10-12 days later an email told me I had cleared the screen and was moving on to the loop. The loop is usually squeezed into a single day and holds 2-3 rounds; in my case there were two, both on the same day.

Loop 1
This was the HLD round. We talked about high availability, RDBMS versus NoSQL, why I would pick NoSQL and what trade-offs come with it. I also had to pin down functional requirements, for example whether a 2-second lag in system updates would be acceptable. The interviewer was evaluating practical thinking, common sense in system design, and whether I stick to sound engineering practice. I didn't find it particularly hard.

Loop 2

• This one began with a CV deep dive. The interviewer probed my automation knowledge, my grasp of CI/CD, and the best practices I follow when implementing things.

• Then came a Dynamic Programming question, which I solved fast. The interviewer asked me to optimize it further after that.

This is mostly the Role Related Knowledge (RRK) round.

Everything up to this point was elimination: fail any one of these rounds and you're out.

The next day the recruiter called to say I had cleared the loop and would go on to another technical round, the As-Appropriate (AA) round. On the very first screening call I had been told that the AA round carries the most weight, since it is where Microsoft decides whether a candidate goes forward.

As-Appropriate (AA)

This round was mostly behavioral, plus one HLD question about a live data stream and visualization.

Key takeaways for the AA round:

• For a senior candidate the interviewers mostly want to gauge leadership. If your target is a Senior Software Engineer role, line up solid stories from your earlier work that make your leadership obvious.

Here is a short story of mine as an example. On one project I headed up work to examine logs travelling across several Apache Kafka hops in a distributed setup. I built a simulator that emitted synthetic logs shaped like multi-hop Kafka traffic. With it the team could rerun assorted scenarios, probe edge cases, and confirm the system held up, all before the real pipeline existed in finished form.

• Brush up your HLD skills. You may not get to draw a diagram in this round, so you have to carry it with how you present and communicate, although in some cases they will ask you to draw one in an editor.

My preparation advice for Senior SDE roles:

1. Prepare easy and medium coding questions.
2. Have a solid understanding of engineering practice and software components.