Hello leetcoders,
I hope everyone is keeping safe. I am so grateful for this community, it has amazing people who have helped me in reaching the goal which felt distant a year ago. I am writing this post after solving around 400 leetcode problems and facing N number of rejections in the past 6 months.
My strategy was to first understand a particular pattern or a data struture and then solve atleast 10-15 problems on that topic and then revise these topics and solve the same problems after regular intervals. I found my self getting better at the concepts with time. It was a gradual process it took time of around 6 months to reach that level of confidence.

March 2021: I got a call from a recruiter through Linkedln. Interview was scheduled after 10 days.

Round 1: It was an online test with 2 medium level questions. I am adding the link below.
https://leetcode.com/discuss/interview-question/1112027/oa-microsoft-march-2021
Had to score atleast 50 percent, I was able to clear this round.

Virtual Onsite rounds:
3 rounds were scheduled on the same day. Every round was an elimination round.

Round 2: 2 medium level leetcode questions.
https://leetcode.com/problems/longest-palindromic-substring/solution/
Explained the different approaches and their tradeoffs and then wrote production ready code for the most optimal approach.
Another question was similar to merge different size files into 1 file with minimum cost, I solved it using Priority queue after discussing different approaches.
Got a call from recruiter after 10 mins, the feedback was positive.

Round 3: It was mostly Problem solving/ Low Level design round. I was asked to design In-Memory file system. Here I was expected to define proper classes using SOLID and OOPS concepts, then asked to write some functions to retrieve files with different filters.
I was able to perform well in this round. I cleared this round as well.

Round 4: This was a High Level Design Round. I was given a choice to design any system, I chose Instagram then we discussed Instagram Live feature. Had a good discussion about scalabality, how to handle load, how to retrieve followers etc, discussed tradeoffs of different appraches. I was expected to design different componentes present in the system. It felt like a discussion round, I enjoyed it.

I got a call from recruiter that I clreared the round but the Hiring Manager round will happen the next day.

Round 5 : Hiring Manager Round: It started with a discussion on my resume and various projects I have done. Some behavioural questions. I was performing well so far, then a coding question was given to me.
https://leetcode.com/problems/basic-calculator-ii/
I was able to explain the right approach but it took some time and I got nervous and wasn't able to code properly. I felt blank and thought I blew up my chance. The interviewer asked that why am I not able to code even after telling the right approach. I was disappointed with my self. I tried to act normal but I wasn't.
The interview ended on a neutral node and I knew I will be rejected.

Feedback:
I didnt recieve any feedback from my recruiter even after 2 weeks. I lost all hopes, sent them multiple mails but no answer. Then one day, I received a mail from the HR that they have recieved a positive feedback and they would like to go ahead.
Though I didn't like the way they Ghosted out and ignored my mails for 2 weeks. I decided to move ahead.

I finally recieved offer after 1 month of completion of all rounds. The process has been really slow. I know these are hard time for us in India, it might have impacted the whole process.

I am happy that hard work finally paid off and I am going to accept the offer.