Microsoft IDC SWE interview: process, rounds and questions

Written by Mentari as typical of this process — not a record of questions Microsoft has asked. Each comes with the follow-up a good interviewer asks next and what they listen for in the answer. Scenario details are our framing, chosen to fit Microsoft’s sector.

1. 01 Merge overlapping intervals. Explain the approach before you write a line.

   Follow-up · Intervals now arrive as a stream and you must answer "how many open right now" at any moment. What changes?

   Listens for · Sort-and-merge explained first; a sensible move to a sweep or heap for the streaming variant.

2. 02 Check whether a string of parentheses with wildcards can be balanced.

   Follow-up · Your solution is exponential. What state can you track to make it linear?

   Listens for · Recognises the min-max open-count idea on prompting; states the new complexity.

3. 03 Walk me through the architecture of your main project and one choice you would reverse.

   Follow-up · What if the number of users grew a hundredfold overnight — what breaks first?

   Listens for · Ownership, a technical opinion, and a what-if answer that names a specific first failure.

Compiled from 7 candidate reports (2023–2026) and the official hiring page. Where reports differ, the range is shown rather than one number.

Online assessment — reported configurations — Two shapes recur: coding-only (two problems in about 60–90 minutes), and a CS-fundamentals MCQ round of about 20 questions in 30 minutes followed by two coding problems in 60 minutes. An August 2024 IDC drive used three CoCubes problems in 75 minutes weighted 2, 3 and 5 marks. A conventional aptitude paper is not consistently reported.^8,7,9,12

1. Solve two medium problems in an hour, then three in 75 minutes, saying the plan out loud before typing. Both reported assessment shapes are timed coding; interviewers then expect the approach explained first.
2. Revise CS fundamentals as MCQs — algorithms, C/C++, OOP, memory, architecture — for 30 minutes a day. Some drives open with a 20-question fundamentals test.
3. Name the naive solution first, then the better one, and the cost of each. Optimisation follow-ups are the differentiator in the second interview.
4. Prepare project "what-if" answers: what if the data were ten times larger, what if a dependency disappeared. The second interview asks "what if" scenarios about your projects.
5. Practise finishing a problem by explaining the remaining algorithm aloud when time runs out. Candidates report partial credit for a clearly explained unfinished solution.
6. Read Microsoft’s technical-interviewing page and rehearse clarifying an ambiguous problem before solving it. Microsoft says it watches how candidates clarify ambiguity and plan within 45 minutes.

What Microsoft says it assesses

• "You’ll have an initial interview and, if selected, a second final interview"; "all our interviews are virtual"; coding or a portfolio may be asked for¹
• "Structured interviews and consistent framework help us evaluate real skills against the role’s requirements" — and "how you’ll learn, collaborate, and contribute to impact across teams"²
• Technical interviews focus on "problem-solving and the skills needed for the role", including design; interviewers watch how candidates break down problems, clarify ambiguity, plan and manage time in a 45-minute round³

What candidates report being probed on

• Whiteboard DSA — valid parentheses with wildcards, merge intervals, the celebrity problem, tree and graph traversals — pushed to the optimal solution^10,8
• Explaining the approach and the code, with complexity, before and while writing^10,8,7
• Projects: technology choices, challenges, "what if" scenarios^8,7
• OOP, OS and DBMS fundamentals; basic design^8,9
• Partial credit for a clearly explained algorithm when the code is unfinished⁸

Microsoft’s campus loop is short, virtual and entirely technical, and it is the one in these guides whose official pages come closest to describing it: an initial and a final interview, structured, with the technical-interview page saying what is watched — how a candidate breaks down a problem, clarifies ambiguity, plans and manages time in 45 minutes. Candidates confirm the shape: a coding test, then two interviews on one day that start with DSA and move into projects and fundamentals, with the second adding design and a few HR questions.

What distinguishes the interviews from a pure problem drill is the weight on explanation. One 2024 candidate reports the interviewer stating the style upfront — explain the approach and the code — and another reports partial credit for a second problem left unfinished because the algorithm was clearly laid out. Optimisation follow-ups and test-case reasoning are the recurring differentiators; the celebrity problem pushed to its elimination solution is the kind of step that decides a round. Treat this page as a map of the rounds and the signals; problem drills live elsewhere.

Where the sources disagree

Official pages and campus accounts converge on two interviews and virtual delivery and leave the assessment to the candidates, who report three versions: two problems in 90 minutes (October 2024 campus intern drive), three CoCubes problems in 75 minutes with weighted marks (August 2024 IDC drive), and 20 MCQs in 30 minutes followed by two problems in 60 minutes (a campus internship account updated July 2025). Preparation sites in 2026 give two problems in 60 minutes and 2–3 in 60–75, consistent with the coding-only version. Each account since mid-2024 counts two interviews, which matches the official "initial … final" framing. Academic filters of 7.0–7.5 CGPA appear in campus notices and an IIT Roorkee account; none is a Microsoft rule, and the Roorkee candidate explicitly notes that the reported coding cut-off was not officially declared.

4. 04 In a party of n people, find the celebrity — everyone knows them, they know no one. Brute force, then better.

   Follow-up · Why does your elimination step never discard the celebrity?

   Listens for · The O(n) elimination, and the invariant behind it explained.

5. 05 Return the first non-repeating character in a stream of characters, at any point.

   Follow-up · The stream is now Unicode, not ASCII. What changes about your counts?

   Listens for · Queue plus count map chosen deliberately; sees that the structure, not the alphabet, is the point.

6. 06 Design a simple URL shortener. What do you store, and how do you generate keys?

   Follow-up · Two requests shorten the same URL at the same moment. What happens?

   Listens for · Basic design with a key scheme; recognises the race and names a fix.

7. 07 Time is up and your second problem is half coded. Tell me the rest of the algorithm.

   Follow-up · What is its complexity, and what test case would you run first?

   Listens for · A clear algorithm under time pressure — the partial-credit path candidates report.

8. 08 Tell me about a time you had to learn something quickly to unblock a team.

   Follow-up · What did you get wrong at first, and how did you find out?

   Listens for · The learn-and-collaborate signal Microsoft names, shown through a specific mistake.

Your project kept everything in one Postgres table. What if the data grew a hundredfold overnight?

Weak · "Postgres scales vertically, so I would move to a bigger instance and add read replicas for the load."

Stronger · "Rows, or reads — which grew? My hot path was a query on user and date, so the first question is whether that index still fits in memory at the new size. After that it is partitioning: by date keeps writes local and makes old months cheap to drop; by user keeps my hot query on one partition. For this workload I would partition by month and keep a user index inside each partition, and accept that a cross-month query fans out."

Why the follow-up lands · The interviewer asks "what breaks before you partition anything?" The strong answer has already looked at the index and memory; the weak one has only a bigger box.

Illustrative — yours must be true.

A Microsoft IDC campus drive is a timed coding assessment — sometimes with a short fundamentals MCQ round first — and two virtual technical interviews on one day. Microsoft publishes the interview shape and what it watches but no test pattern or cut-off; The CGPA screen belongs to the college, not the firm. What a cell can move is coding under the clock and talking a solution through.

Coding problems are outside Mentari’s scope; what its software-engineer mock covers is the conversational half of the Microsoft loop — clarifying an ambiguous problem, project what-ifs, fundamentals talked through and the design and HR questions in round two. Run Microsoft-pattern mocks for a whole batch.

• Software engineer mock interview
• Google interview
• Amazon interview
• Is ChatGPT a Good Mock Interviewer?
• STAR Method Answers That Survive Follow-ups
• All company guides →

1. Student interviewing — hiring tips — Microsoft Careers (official) · official · accessed 2026-10-23 · initial and final interview; all virtual
2. How we hire — hiring tips — Microsoft Careers (official) · official · accessed 2026-10-23
3. Technical interviewing — hiring tips — Microsoft Careers (official) · official · accessed 2026-10-23 · what interviewers watch in a 45-minute round
4. Microsoft India Development Center — Microsoft (official) · official · accessed 2026-10-23
5. Explore Microsoft — Microsoft Careers (official) · official · accessed 2026-10-23
6. Microsoft careers — India — Microsoft Careers (official) · official · accessed 2026-10-23
7. Microsoft interview experience set 125 — on-campus for IDC — GeeksforGeeks · candidate report, 2024-08 · accessed 2026-10-23 · CoCubes: three problems, 75 minutes, weighted 2/3/5
8. Microsoft interview experience — software engineering internship (October 2024 campus drive) — GeeksforGeeks · candidate report, 2024-10 · accessed 2026-10-23 · two problems in 90 minutes; two same-day interviews
9. Microsoft interview set 20 — campus internship — GeeksforGeeks · candidate report, 2025-07 · accessed 2026-10-23 · page updated July 2025; 20 MCQs in 30 min then two problems in 60
10. Microsoft interview experience — SWE intern, off-campus 2024 — GeeksforGeeks · candidate report, 2023-09 · accessed 2026-10-23 · older account; cited for interview content (celebrity problem, intervals)
11. Microsoft on-campus placement and interview questions (IIT Roorkee) — GeeksforGeeks · candidate report, 2023-12 · accessed 2026-10-23 · older account; three coding questions; cut-off "not officially declared"
12. Microsoft placement papers — test pattern and syllabus (2026) — FACE Prep · candidate report, 2026-05 · accessed 2026-10-23 · preparation-site compilation
13. Microsoft eligibility criteria for freshers 2026 — FACE Prep · candidate report · accessed 2026-10-23 · preparation-site compilation

Verified October 2026 by Sumit Mishra, Mentari founder. Spotted an error, or represent Microsoft? Write to [email protected] — we acknowledge within two working days and correct or remove a disputed statement within 72 hours.

Mentari is not affiliated with Microsoft. This page is pattern-based, compiled from the public sources listed, and is not insider information. Candidate-reported details are reproduced as patterns only, in our own words.