Not going to directly say the questions due to NDA.

Background
3YOE in software
Experience at small-mid sized companies
First time ever interviewing at a BigN
First time ever doing LeetCode as well lol
Underpaid at my current company and wanted a big upgrade in Canada (personal reasons). Started loosely preparing LC way back in December then ramped up as time went on. I completely forgot all my DS&A so I didn't even know what a BST was starting out.

Application
Applied with referral in April 2020, got AMCAT link a few days afterwards. Did the OA 6 days later in early May.

AMCAT Online Assessment
Both questions were ones listed in the Amazon OA thread. Critical Connections/Routers were NOT on the OA, which I was actually kinda sad since I prepared a lot for them.

Virtual Onsite
Got positive feedback from the OA and recruiter scheduled onsite, I picked end of May (2 weeks away). I'll talk about my prep process at the end of this post.

Round 1: Coding
LP questions
Not on the Amazon card but similar to one of them on there, medium level. Finished ahead of time and asked interviewer a bunch of questions.

Round 2: OO
LP questions
This one REALLY threw me off. Basically it started off making some simple methods to manipulate data, then got more complicated. I think it was testing my knowledge of inheritence/polymorphism in a vague way. I got what he was asking for but I had never done anything like it and couldn't implement it in code. Bombed this round.

Round 3: Systems Design
LP questions
Asked me to design a component that could be part of a system. Bombed this one, I had actually been aware this could be a question, but I didn't read through the solution. I was able to work through most of a solution with the interviewer but needed many hints.

Round 4: Coding
LP questions + a medium level LC question. Not on the Amazon card either but if you've done the card, this one is pretty easy. Finished ahead of time as well.

Round 5: Behavioural
50 mins LP

After the interview I was thinking I bombed, hoped to get downleveled to SDE1 if I was really lucky. Alas, it wasn't to be. Recruiter got back to me after a couple of days to let me know of the reject. Said I could apply again in 1 year (??? thought it was 6 months)

Prep

• 160 LC questions - 90 medium, 15 hard, 55 easy
  I was aiming for 1 question a day and then picked it up to 3-4/day in late March as I was getting ready to apply. I did BFS approach to questions, as I felt many DS&A was brand new knowledge to me. Then I'd revisit those basic concepts later to get a DFS understanding of them.
• did the Amazon card which was very helpful
• Some CTCI chapters
• r*kking the Systems Design
• some practice interviews on P**mp
• reviewed all the LPs and made 2 stories for each
• various Youtube channels on LC and Systems design

Takeaways

• Round 2 (OO) was by far my worst round and likely killed my chances. SD and OO I didn't study enough for and thought I could "intuitively" reason my way through any problems as I had a template in mind for approaching basic versions of these questions. Unfortunately, with these interviews, breadth of knowledge seems to be a better approach.
• Should have iterated more on my LPs. I could tell one of the interviewers was expecting a stronger story than the one I had provided for. It was something involving me doing something new, he was likely expecting new technology but my answer was based on processes. I also was asked the same questions a few times and had mutate another story I hadn't used yet into a weak example. Not sure how much that hurts your chances to use the same story again, but I didn't want to give off the impression my experience was small.
• I didn't feel like I truly got comfortable in LC until around 140 questions. I focused on memorizing what tools I had, and how some structures actually worked. AVOID MEMORIZING SOLUTIONS. You will just forget how to do basic questions by trying to recite the solution you have memorized and then failing (unless your memory is amazing), you're better off analyzing the question, thinking of possible solutions and then executing on that.
• Take a break! I was working full time during the entire process and I was feeling burnt out and demoralized at many points. For some weeks, I went back to doing 1 LC question a day and let my brain breath.
• Overall the interview wasn't that difficult, I feel. If you happen to know a lot and are prepared, you'd do well on the interview. Amazon is really looking for a well-rounded engineer. I never thought I'd be saying this but I wish they focussed more on LC only lol.