Microsoft Interview Experience — Selected 🎉

After applying to Microsoft more than 20 times through their careers page, I finally got the opportunity to interview with them.

The process had 5 rounds in total. The first four were technical rounds, each lasting around 70–80 minutes, followed by a 40-minute techno-managerial round.

Round 1 — Technical

The interview started with a brief introduction and resume discussion, which took around 10 minutes.

After that, we discussed 2 problem-solving questions.

The second question was based on Binary Search, where I had to find the minimum number of API calls required to achieve a certain result.

Round 2 — Technical

This round began with a detailed discussion about my resume.

Since I had mentioned technologies like React, Elastic Search, SQL, and NoSQL, the interviewer asked about:

• Architecture of frameworks like React

• Elastic Search

• Differences between SQL and NoSQL databases

This discussion lasted around 20 minutes, after which we moved on to a coding problem.

Problem

We were given a 2D room with infinite points and a list of motion sensors represented as (x, y, r).

Here:

• x and y represent the sensor's location.

• r represents its detection radius.

The task was to determine whether it was possible to start from one end of the room and reach the other without being detected by any motion sensor.

After discussing the problem for around 20 minutes, I came up with a BFS-based solution.

We then discussed the time and space complexity of the solution.

Round 3 — Technical + Design

The round started with an introduction and a discussion about my previous projects.

I was asked questions such as:

• What was the most challenging project you worked on?

• What did you learn from your previous projects?

We then moved on to a DS-related question and a design question.

Design a Logging System

This was an open-ended Low-Level Design problem.

The interviewer mainly focused on OOP concepts and design patterns.

I designed the required classes and common functions and discussed using the Singleton pattern to maintain a centralized logging system.

Towards the end, the interviewer spent around 10 minutes explaining the team I would be joining and the kind of learning opportunities I could expect.

Round 4 — Technical + High-Level Design

This round again started with an introduction, resume discussion, and questions about my previous projects.

Some of the questions were:

• What was the most challenging project?

• What problems did you face?

• How did you solve them?

There was also a detailed discussion around SQL and NoSQL databases, followed by a High-Level Design problem.

Design a Reminder App

This was another open-ended design discussion where we first discussed the requirements and then worked through the basic components.

One key requirement was that if the mobile device is offline, the notification should still be delivered through other connected devices such as:

• Laptops

• Speakers

• Smartwatches

• etc.

I discussed concepts like long polling and message queue systems to approach this problem.

Round 5 — Techno-Managerial

The final round was relatively short and precise, lasting around 40 minutes.

It started with an introduction and some discussion about my previous projects.

I was then asked about encryption techniques, followed by another design problem.

Design a Search Autocomplete System for Windows File Search

I approached the problem using a Trie data structure.

The interviewer then asked follow-up questions around optimizing Trie updates and node insertion.

Result — Selected

The entire interview process took around 20 days.

All the interviewers were friendly and supportive, and they gave hints whenever I got stuck. So, one thing I learned is that it's really important to listen carefully and pick up on those hints during the interview.

I received the offer letter just 2 days after the 5th round.