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Microsoft interview notes, page 39 of 60

FAANG / Big Tech

Most of these Microsoft write-ups come from Software Engineers (372), then Product Managers (124) and Machine Learning Engineers (53). The most reported rounds are the technical phone screen (255), the product sense round (111), the system design round (93) and the behavioral / leadership round (49).

597 interview notes · updated Oct 2026

Microsoft·Software Engineer·Technical Phone Screen

Jun 2026
Microsoft SWE interview with a linked list problem that looks manageable until you're actually in it. The in-place constraint is where things get interesting.
  • Given the head of a singly linked list and an integer k, reverse the nodes in groups of k in-place. If the final group has fewer than k nodes, leave them as-is. Walk through your algorithm and implement it.

“I knew the rough idea pretty fast, reverse chunks of k, stitch them back together, move on.”

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Microsoft·Data Scientist·Technical Phone Screen

Jun 2026
Microsoft Data Scientist interview that was basically one giant coding question dressed up as a system design problem. They wanted a full k-means implementation from scratch, production-ready, with all the edge cases handled. Pretty intense for a single session.
  • Implement k-means clustering from scratch in Python without using any ML libraries. The function should support k-means++ initialization, multiple restarts, and return the best result by inertia.
  • How would you handle empty clusters during k-means, and can you implement a strategy for it?
  • What numerical stability issues can arise in k-means and how would you address them? Should the implementation support feature standardization?
  • Analyze the time and space complexity of your k-means implementation in terms of n, d, and k. Then describe a mini-batch variant and explain when you'd prefer it.
  • How would you choose the right value of k, and how would you evaluate whether your clustering is stable across different random seeds?
  • Write unit tests for your k-means implementation covering degenerate cases like n less than k, duplicate points, high-dimensional data, and convergence behavior.

“This was the core of the whole interview.”

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Microsoft·Product Manager·Onsite - Product Sense / Strategy

Jun 2026
Interviewed at Microsoft and got a product strategy question about Apple Watch segments, which felt a bit odd given the company but whatever, that's how these things go sometimes.
  • What are the top customer segments for the Apple Watch?

“Felt weird getting a question about a competitor's product in a Microsoft loop, but I just rolled with it.”

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Microsoft·Software Engineer·Technical Phone Screen

Jun 2026
Microsoft SWE interview with a tree problem that started simple and then got harder. The BST version felt manageable but the follow-up to a general binary tree without ordering guarantees is where things got real.
  • Given the root of a binary search tree and two nodes p and q that are guaranteed to exist, find their lowest common ancestor.
  • How would your approach change if the tree is a general binary tree with no ordering property? Walk through an algorithm and analyze its complexity.

“The BST property makes this pretty clean once you think about it.”

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Microsoft·Software Engineer·Technical Phone Screen

Jun 2026
Interviewed for a security analyst role at Microsoft, got hit with an incident response scenario pretty early on. Not a lot of fluff, they wanted to see how you think under pressure.
  • Walk me through the steps you'd take if you discovered an active security compromise on a client's machine.

“I started with containment and worked outward, isolation first, then preservation of evidence, then escalation.”

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Microsoft·Software Engineer·Onsite - Product Sense / Strategy

Jun 2026
Interviewed for a BA role at Microsoft and got hit with a competitive analysis case. Pretty standard stuff for that level but I fumbled the structure more than I'd like to admit.
  • A competitor is gaining market share. How would you investigate why?

“I jumped straight to 'look at their pricing' which, in hindsight, was way too narrow.”

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Microsoft·Software Engineer·Hiring Manager Screen

Jun 2026
Interviewed for a Customer Success Manager role at Microsoft, just one question from what was shared. Pretty standard behavioral territory but it's the kind of thing that sounds easy until you're actually sitting there trying to say something that doesn't feel rehearsed.
  • What does a growth mindset mean to you?

“I fumbled this a bit.”

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Microsoft·Software Engineer·Technical Phone Screen

Jun 2026
Microsoft SWE interview that mixed a classic LeetCode problem with a trickier follow-up involving union-find. The first part felt manageable but the second one required a different mental gear entirely.
  • Find the kth largest element in an unsorted array.
  • Given an m x n grid starting as all water, you receive a sequence of operations that each convert a cell to land. Return the number of distinct islands after each operation.

“Went with quickselect after briefly mentioning the heap approach.”

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Microsoft·Machine Learning Engineer·Onsite - System Design / Architecture

Jun 2026
Microsoft ML Engineer interview that was basically a deep dive into post-training pipelines. One long design question covering SFT and RLHF end to end. Felt more like a research discussion than a standard system design round.
  • Design a complete post-training pipeline to improve an LLM's consistency and alignment, covering supervised fine-tuning and reinforcement learning from human feedback including data sourcing, reward modeling, training choices, and evaluation.

“This was a single question that ate the whole session.”

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Microsoft·Data Scientist·Technical Phone Screen

Jun 2026
Microsoft Data Scientist interview with a pretty involved coding question that blended algorithm design with correctness proofs and test case generation. Single question but they really dug into every layer of it.
  • Given a non-decreasing integer array that has been rotated an unknown number of times (with possible duplicates), write a function returning both the rotation point index and the leftmost index of a target value. Walk through your algorithm idea, correctness argument, complexity analysis, and write thorough unit tests covering edge cases like all-equal arrays, target spanning the rotation boundary, single element, and empty input.

“This one took me a while to untangle.”

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