Microsoft Interview Experience | Off-Campus for SDE Internship

I applied to Microsoft through one test 2019 about which I was informed by our college TPO for Internship as a software development engineer. All of the candidates who applied were invited for an online coding test on mettle platform.
Online Coding Round:-

Three questions were given in 90 minutes of time to solve. All questions were of equal weight .

• Question 1: Check for balanced parentheses in expression and display the count of parenthesis.
  https://www.geeksforgeeks.org/check-for-balanced-parentheses-in-an-expression/
• Question 2: Print the maximum sum of the contiguous sub-array in a separate line for each test case.
  I did it using Kadane’s Algorithm
  https://www.geeksforgeeks.org/largest-sum-contiguous-subarray/
• Question 3: Write a function that reverses a string without inbuilt function.
  https://www.geeksforgeeks.org/program-reverse-string-iterative-recursive/

I was able to do all the 3 questions completely.
Key to cracking this round is to try to write as an optimal solution as possible.

After around 2 weeks the next round was scheduled which was on skype. All students who were able to complete at least 2 questions in the coding round were invited.
It went for about 50-55 min. Interviewer initially introduced himself and told me the procedure for that round.
There were 3 questions.

• Question 1: Maximum number of 2×2 squares that can be fit inside a right isosceles triangle.
  https://www.geeksforgeeks.org/maximum-number-2×2-squares-can-fit-inside-right-isosceles-triangle/
• Question 2: Recursively Reversing a linked list
  https://www.geeksforgeeks.org/recursively-reversing-a-linked-list-a-simple-implementation/
• Question 3: Print all possible words from phone digits
  https://www.geeksforgeeks.org/find-possible-words-phone-digits/he asked me recursive approach for this.

This round was completely based on recursion for me. I was able to answer 2 questions. Then, in the end, he asked me if I have any queries related to it. He also cleared my doubts at the end.

All students who qualified this round were invited to Microsoft Office for the further interview process.

Group Fly Round:–

Around 30-35 students appeared for the group – fly round. It was a pen-paper test. We were provided with many questions based on mathematics, and one question on arrays to be solved in 60 minutes.

We have to write the whole program from input to output. They were also expecting an optimized solution. You are allowed to use any language.

Note: – Try to write clean code as possible and use meaningful variable and function names.

Nearly 20 students were selected for the next round.

This was the final round.

My interview was taken by a senior person. He asked to me introduce myself. The interviewer first went through my resume. He then asked me to explain one of my projects. He asked me to make the ER diagram for it and about the normalization in its database.
He asked me about my favorite subject. I said OS and then he asked me some questions related to it. After that, he asked if I had any questions for him. I asked a few questions and it was over.

The interview went for around 25 minutes.

Final Result was declared within 2 hours and I was not selected. 19 students were selected.

The total interview process was conducted from around 9 am to 4 pm.