The Microsoft Process
Online assessment / phone screen → several technical rounds → 'as-appropriate' final round, often with a hiring manager.
- Coding: arrays, strings, trees, graphs, recursion, DP
- Emphasis on clean code, edge cases, and clear communication
- System design for experienced candidates
- Behavioural: teamwork, growth mindset, handling ambiguity
Common Interview Questions & Answers
Q1. Reverse a linked list.
Iteratively re-point each node's next to the previous node using three pointers (prev, curr, next). O(n) time, O(1) space; a recursive version also works.
A classic — be flawless and mention both iterative and recursive.
Q2. Find the k-th largest element in an array.
Use a min-heap of size k (O(n log k)) or Quickselect (average O(n)). State the trade-off between them.
Mention Quickselect for the optimal average case.
Q3. Check if two strings are anagrams.
Compare character counts (a 26-length array or hashmap) — O(n); or sort both and compare — O(n log n).
The counting approach is optimal.
Q4. Serialize and deserialize a binary tree.
Use pre-order traversal recording nulls as markers to serialize; rebuild recursively from the same order to deserialize.
Recording nulls is what makes reconstruction unambiguous.
Q5. Tell me about a time you learned something quickly. (growth mindset)
STAR: an unfamiliar technology/problem, how you ramped up, applied it, and the result — Microsoft prizes the learn-it-all mindset.
Microsoft explicitly values 'learn-it-all' over 'know-it-all'.
Q6. Find the lowest common ancestor in a binary tree.
Recurse: if the current node is null or one of the targets, return it; recurse left and right — if both return non-null, the current node is the LCA.
Explain the both-sides-non-null insight clearly.
Q7. How would you design a system like Microsoft Teams chat? (system design)
Discuss requirements, message storage, real-time delivery (WebSockets/pub-sub), presence, scaling, and consistency trade-offs.
Clarify scope and scale before drawing boxes.
Q8. Detect if a binary tree is a valid BST.
In-order traversal must be strictly increasing; or recurse passing down valid (min, max) bounds for each node.
The min/max bounds method avoids the equal-values pitfall.
Q9. Tell me about a conflict in a team and how you resolved it.
STAR: the disagreement, how you listened, found common ground with data, and reached a constructive outcome.
Show empathy plus a concrete resolution.
Q10. Implement an LRU cache.
Combine a hashmap (O(1) lookup) with a doubly linked list (O(1) move/evict); on access move the node to the front, evict from the back when full.
The hashmap + DLL combo is the expected answer.
Common Mistakes to Avoid
Messy code and unhandled edge cases
Not talking through the approach before coding
Ignoring system design for experienced roles
Flat behavioural answers with no growth-mindset angle
Expert Tips
Write clean, readable code and state your complexity
Always enumerate edge cases (empty, single, duplicates)
Communicate continuously — Microsoft weights collaboration
Prepare growth-mindset behavioural stories
Pre-Interview Checklist
5 itemsFrequently Asked Questions
Is Microsoft's interview harder than TCS/Infosys?
Yes — it's a product-company bar focused on DSA depth, clean code and problem-solving, versus the fundamentals-and-communication focus of services firms.
Does Microsoft ask system design to freshers?
Rarely in depth for new grads; it's mainly for experienced roles. New grads focus on DSA and clean coding.
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