Backgroud: Masters from Tier-1 College in CS.
Experience : 1.8 year experience (1 year internship not included)
Current company and Ctc : Top product based Semiconductor company; 15 lpa

Thank you Leetcode community. It's my turn to give back. It was an amazing opportunity to interview with Amazon.
It's been a year for me to prepare and enhance my coding. I will write a detail experience about my journey to help everyone who want to join Amazon.

How I applied?
I sent my resume to an Amazon employee and he reffered me. After around 20 days(Feb, 2021) got a mail from recruiter for online coding round and
they asked me to complete within a week.

1. Round 1 - Online Coding Round : There were 2 coding question and I was able to solve both of them.
   1st question was related to heap and other BFS. Both were Medium level questions.

   Got an email from the recruiter next day(16th Feb, 2021) that they will schedule four interview rounds and they will call me soon to discuss.
   They had given me 1 month of preparation time and scheduled interview on end of March. I don't know they give this much amount of time for
   preparation to others or not.

   The 3 sections of the assessment

   Coding challenge (2 scenarios) and Coding approach (elaborate why you code the way you do) - 105 minutes
   Work style survey - 15 minutes
   Feedback survey - 5 minutes

2. Round 2 - Coding Round with SDE2 (10:00 AM):
   Interview started with the introduction of the interviewer and then he asked me to tell about myself. (~6 mins)
   Then some basic OS question : Process and thread. Difference between them and how they work. (5 mins)
   Coding Question : No. of Islands. This is standard leetcode question asked by Amazon. ( 20 mins)
   I already solved this question earlier so I knew the approach as well. I started with a brute force solution and then moved to the optimized approach.
   I was asked to write the optimized solution in production level code and asked me assume the best cases as well.
   Atlast I was asked to dry run the code and explain the code line by line and write the time complexity and space complexity.
   Interviewer was okay with my solution.

   Next question was related to string and had to find longest substring of size K. I gave the brute force solution but was not able to come up with the optimized
   solution. (~15 mins)
   He told me to write the brute force solution and do the code walk through. In the end he told me that I was missing one base case in my solution.
   I tried to find that missing test case but I was not able to find it. (I think this is the reason I was rejected).
   In the next ~5-6 mins he asked me some LP's and I was able to answer them based on my experience.

3. Round 3 - Coding Round with SDE2 (11:30 AM):
   2 Coding questions:

   1. Find the longest substring without repetiting character (https://leetcode.com/problems/longest-substring-without-repeating-characters/)

   2. Kth Largest Element in an Array (https://leetcode.com/problems/kth-largest-element-in-an-array/submissions/)
      Able to solve both questions and interviewer was satisfied.

   In the end I was asked 2 LP. I really felt good after this round as I was able to answer all the questions.

I thought I am done for today but around 2:00 Pm I got a call from the recruiter that he is scheduling a managerial coding round at 3:00 PM.
I told him that I will be available for the round.

4. Round 4 - Managerial coding round with 2 SDM's
   Quick intro about the Managers and my intro. (~7-8 mins)
   2 LPs (~6-7mins)
   So far so good.
   Coding Question :

   1. Word Search https://leetcode.com/problems/word-search/ (~ 20 mins)
      Able to solve and explain the approach to the interviewer.
      Wrote the time complexity and space complexity as well in the end)

   Around 15 mins left.
   2. Calculate the angle between hour hand and minute hand
   I told him my approach but was not able to come up with the correct answer. He mentioned I am going in the right direction and told me to write the
   code for my approach. As I had not came up with the correct logic I was not able to think how to code it. I wrote pseudocode and explained it.
   (This can be reason for my rejection)
   In the end they asked me if I had any question.

   All the interviewers were very friendly and guided me whenever I stucked.

Next day I got a rejection mail. I didn't thought that I will be rejected. I was able to solve almost all coding questions. I prepared all the LP's
based on my experience and was confident in all interviews.

I have written the reasons that may led my rejection. Hopefully this will help other candidates while preparing. I wish you luck.