This is to share some highlights of my interview so that my experience will be useful to others who are preparing for the Amazon SDE1 L4 interview.
The technical questions asked throughout all the rounds (all are from the Leetcode):
Coding assessment:
Question 1: https://leetcode.com/problems/rotting-oranges/ [this question was worded very differently, the context was different and took me 5 mins to understand that the logic was exactly similar to the rotten oranges). I Solved this using BFS.
Question 2: I cannot recall the question, but it was very similar to the question from the leetcode discussion platform - “extracting most popular features out of a feature set…” This is generally solved using a priority queue. It is of Medium level difficulty. Again, the wording of the question was different.
I passed all the test cases for Q1.
I passed 18/21 test cases for Q2.

Telephonic Round:

1. Zigzag level order traversal of a Binary Tree. [I solved it using a queue. follow up: can you tell me if you can solve it using different DS in the same time complexity? – answer: use stack]
2. “We are given consecutive natural numbers from 1 to N.
   Input: list of N-1 numbers unordered. (with one missing number)
   return the Output: The missing number.” – this was easy.
3. Interviewer asked me general questions about my experience and some questions specific to a particular project that I did. (I can’t recall the specific question, as it happened 40 days ago).

Success Tip that worked for me (which I lacked in my past interviews):
Writing the code really fast after discussing the approach – which comes through a lot of practice.
Walking through Your Code by passing a few inputs to check your code validity. I cannot believe that I was able to rectify at least 3-4 parts of my code while talking aloud. The interviewer seemed happy to see me rectifying them.

Throughout the interview, the interviewer kept asking questions to justify the approach, the usage of specific data structures that I thought of and the time and space complexities.
Onsite Virtual (Rejected):
My experience on LP’s:
The LP’s asked were a bit open ended in most of the rounds. I was free to choose examples from my college or from my work experience. I am not sure if this is the case with every other L4 SDE interview. There were follow-ups asked after I started speaking about a situation.
The general questions with respect to LP’s and some of the follow ups in all the rounds are as follows (I remember only some of them):

1. Tell me about yourself, your experience, pick any challenging project that you had worked on and tell me what was the challenge, how did you over come it, why was it a challenge? Did you seek an SME? How did you learning a specific thing (from your context) that you did not know?
   [the interviewer needs to get convinced that the situation was challenging, otherwise he repeats the question].
2. Did you miss a timeline during your work experience, how did you communicate with the other teams/customer? What did you learn? What did you do to not repeat it? Did you skip some of the features?
3. Tell me about a time when you had to disagree with your team? What was the situation? Why had you disagreed? Did you succeed? How? [when I had answered this, I got the follow-up asking “okay, tell me about a time when you had to disagree with the team, but the team still moved forward with their decision, what did you do?]
4. What is your favorite LP? Describe a situation were you had demonstrated the particular LP. [open ended]
5. I was severely measured on the customer obsession, with too many follow ups.

Round1: OOD – different types of Alexa devices are given, each one has to display/output the status of it’s battery charging status to the user. [the question was intentionally vague to check if the interviewee is asking clarifying questions while trying to solve the problem].
Round2: https://leetcode.com/problems/product-of-array-except-self/
Round3: LRU cache [the interviewer started talking about some technical scenario, which lead to the interviewee talking about the cache, and finally asked to implement the LRU cache].
Round4: https://leetcode.com/problems/integer-to-english-words/
In each round, the interviewers talked about tradeoffs using different data structures and different methods of solving each problem.
One suggestion that I can give from my own failure:
If you are preparing for L4 SDE please be 100% prepared with the most frequent questions asked by Amazon. If you are already prepared, please do revise them without feeling bored of revising the same stuff right a week before the interview. It is possible to get stuck up at some point as you have very less time to recall and also because of being nervous, you may end up not solving the problem till the end. It’s always better to re-read/re-solve rather than loosing the interview for not solving the question that you had worked out and solved by yourself some time back.
At this point, I am extremely tired of applying and trying for the full time jobs since 10 months. But I don’t want to give up as I came this far. I want to know if there is anyone in the same situation like me.