Microsoft Software Engineer (SDE) Coding Interview

The Microsoft software engineer interview is broad but not deep. The SDE coding loop spans arrays and strings, trees and linked lists, graphs, dynamic programming, and design-a-data-structure, at LeetCode easy-to-medium, with genuine LC-hard rarer than at Google or Meta. Three things make it Microsoft's own: a first-class object-oriented design (OOD/LLD) round, a separate online-assessment problem bank, and more OS and threading than peers. The bar is clean, readable, tested code that runs, valued over the clever one-liner.

The coding rounds cover a lot of ground without going especially deep. Questions range across the whole pattern map: arrays and strings, trees and linked lists, graphs, dynamic programming, and design-a-data-structure. They sit at LeetCode easy to medium, and genuine LC-hard shows up less than it does at Google or Meta. The breadth is real, so you cannot skip a pattern, but the depth on any one problem stays human. That holds whether you are interviewing for SDE (the entry level) or SDE II (the broad mid-level band most engineers sit in). What changes with level is the design round and the story you tell, not the coding difficulty.

What is the Microsoft software engineer interview?

The Microsoft software engineer interview is a same-day loop of four or five 45-minute rounds. It is usually preceded by a recruiter screen and, depending on your org, either an online assessment or a technical phone screen. The loop mixes two or three coding rounds with an object-oriented design round, and every round opens with a short behavioral block. The coding bar sits at classic medium difficulty. The full process is broken down here.

Under that breadth sits a stable classic core. A small set of problems keeps coming back, year after year, whether the loop ran in Redmond, Bangalore, or Hyderabad. A Premium question is the standout, asked so often it is effectively a Microsoft signature. Clustered around it: a Premium question Characters, Merge Intervals, Meeting Rooms II, four Premium questions, Kth Largest Element, a Premium question, Reverse a Linked List, Rotate Image. Over-prepare those few and you have covered most of what the loop reaches for. This lesson maps the patterns, points you at the paid lessons that drill each one, and names the three things that make Microsoft its own interview.

The Microsoft angle

Clean, readable, tested code beats the clever one-liner. The bar here is correctness and clarity, full stop. Your code has to compile and run, edge cases handled, and read like something a teammate could maintain. Microsoft graders take the solution that is obviously right over the dense trick that saves three lines and hides a bug. Talk through your cases, write a quick test in your head or in the editor, and fix the off-by-one before they point at it. If the pattern fundamentals feel shaky, the free Foundations course drills each one from the base up so these lessons can stay on what makes Microsoft Microsoft.

The recurring core, by pattern

Microsoft runs no standardized question bank; interviewers and teams pick their own sets, which is why the recurring core matters more than any single problem. The favorites cluster in a few places. Edge-case-heavy string and interval work is the widest bucket, leaning on two-pointer, sliding-window, and matrix manipulation. The tree and linked-list classics are the most characteristic cluster, led by the near-universal reverse-a-list warm-up. Grid and graph traversal is rising in the senior tracks. The design-a-data-structure problems bridge into a first-class OOD round, with a Premium question the highest-frequency single item anywhere in the loop. Dynamic programming shows up less than candidates expect and stays one-dimensional. And the online assessment is its own greedy-string universe that barely touches the onsite classics. The lessons below take each bucket in turn and drill its high-return problems as runnable code.

The Microsoft angle

OOD/LLD is a first-class round, so budget for it. Generic interview lists bury elevator and parking-lot prompts as footnotes. At Microsoft a dedicated object-oriented design round is common, and below Senior it frequently takes the slot a distributed system-design round fills elsewhere. The grade there is a clean, extensible class model and the right move on the "now add X" follow-up, not algorithmic cleverness. A Premium question wears two hats here: it shows up as a data-structure problem and as the "design a cache, then extend it to LRU" OOD prompt. Recognize that the two are one problem, prepare it once, and treat the design round as load-bearing rather than a warm-up.

The Microsoft coding questions asked most

A short set of named problems keeps resurfacing across Microsoft SDE and SDE II loops, regardless of the org running the interview. Learn the pattern under each one, not the title, because the title is what teams change. The pattern lessons below work each problem end to end as runnable code, and the deep algorithm walkthrough for each lives in the free Foundations DS&A course.

SDE vs SDE II: how the bar shifts by level

Microsoft's IC ladder runs on hidden numeric levels, and the two you meet most in the loop are SDE at 59/60 and SDE II at 61/62. The coding problems barely change between them. Both levels see the same classic medium patterns and the same recurring core above. What moves is the design round and the depth of the follow-ups. At SDE the design skews object-oriented and lighter, and interviewers mainly want correct, clean code with an approach they can follow. At SDE II the object-oriented design interview carries real weight and often stands in for a distributed system-design round. The coding follow-ups also probe harder on edge cases, complexity, and how your code would hold up in production.

The Microsoft angle

"sde 2 at microsoft" is a leveling read, not a harder LeetCode list. Candidates prepping for SDE II sometimes go looking for a scarier problem set and never find one, because it does not exist. The coding bar is the same medium core. The lever that decides SDE II versus a down-level to SDE is the object-oriented design round and whether your follow-ups show ownership of a real system, not another lap through LC-hard. Down-leveling is common and partly headcount-driven, so treat the leveling and offer mechanics as part of your prep, not an afterthought.

The phone screen and the first gate

Before the onsite loop, most orgs run one screening gate, and which one you get depends on the pipeline. Campus and university pipelines lean on the online assessment. Many experienced-hire team pipelines instead run a technical phone screen: a single 45-to-60-minute call with an engineer, one coding problem in a shared editor, from the same classic medium core as the onsite. The phone screen is a compressed version of a loop coding round, so the same clean-and-tested bar applies, and it usually opens with a few minutes of behavioral. Confirm with your recruiter which gate your role uses, because they prep differently. The phone screen is a live problem you talk through. The assessment is timed and graded against test cases with no human in the room.

The online assessment is a different world

Many loops, depending on the org, open with an online assessment on Codility or HackerRank, two or three problems in sixty to ninety minutes, before any human sees you. The catch is that the OA draws from a recognizable, semi-stable bank that barely overlaps the onsite classics. Its problems lean greedy, counting, and string-flavored, rarely tree-hard or graph-hard. The signature is the no-3-consecutive-letters family, which appears under five different titles but is really one idea. Max Network Rank and minimum adjacent swaps to make a palindrome round out the core.

The Microsoft angle

The OA blindsides pure-LeetCode preppers. Study only "top Microsoft onsite" and you will over-index on trees and DP, then hit a greedy-string OA you never rehearsed. The fix is to treat the assessment as its own preparation track. Learn the no-3-consecutive-letters idea once and you have covered most of the forms it takes; add Max Network Rank and the palindrome-swap problem and you have the core. The online-assessment lesson works this bank directly, because the gate before the loop deserves prep the loop's classics will not give you.

One more Microsoft-flavored corner: OS and threading questions appear more here than at peer companies. "Print 1 to 100 using three threads" and a thread-safe singleton are the staples, alongside producer-consumer and plain conceptual questions about how threads, processes, and virtual memory work. They turn up in real loops, India SDE-II rounds especially. They are absent from the standard algorithm lists, so a candidate who only grinds algorithm tags can be caught flat. The design-data-structures and OOD lessons fold the threading-flavored work in where it belongs.

How these lessons are organized

Each lesson below takes one part of the map. The pattern lessons work the recurring core for that bucket as runnable problems, with the Microsoft framing and the follow-ups the room actually adds. The OOD/LLD lesson runs the design round end to end. The online-assessment lesson drills the separate OA bank. Where a lesson leans on a base data-structures idea, the deep walkthrough lives in the free Foundations course so these stay on what is specifically Microsoft.

Common questions