Background:
- Education: (Tier 1/2) (Bachelor’s in Non-CS branch) (low-ranked NIT)
- Years of Experience: 10 months are working as a Software Developer in Product based Company and before that 6-month intern in the same role.
- Coding Experience: Did GFG and InterviewBit during campus placements { i got my current job through it}, don’t have an account on CodeChef or Codeforces have zero Competitive Programming Experience, Had done no coding since the time I was placed to when I started to prepare again{ approx from sep-2020 to Feb 2022 did no coding}.
Preparation Strategy: Once I gained enough experience in my current job and knew how to handle work there and prepare I started since I believe the experience gained while working in the industry is useful for interviews was proven correct in Amazon.
- Used striver sheet + Leetcode to practice { did around 250 Lc Questions 50 e, 170 m,30h},
- Spend a lot of time learning basics and topics from specific teachers so example Recursion, Sliding Window, Stacks, DP{ Aditya Verma },
- Topics missed by Aditya in Dp { Striver}, Graphs { Riddhi Dutta and PepCoding YT},
- Questions on Arrays Backtracking, etc { Pepcoding YT},
- Leetcode Question Solution { TechDose and Nick white}, Trees, Linked List { Pepcoding YT},
- Heaps { Types of Heaps from Leetcode Post {https://leetcode.com/discuss/general-discussion/1127238/master-heap-understanding-4-patterns-where-heap-data-structure-is-used} and practice questions from it }.
- More than the questions the focus was to know and understand patterns something I picked up from Aditya Verma’s style of Teaching.
- Used striver sheet for both reference while covering a topic and more in-depth for revision also gave around 10-15 LC Contests and was able to solve 2/3 questions consistently and 4 questions on a couple of occasions.
Interview Experience: Time Frame: May-Jul 2022
How did I Apply: I applied via referral to companies like Microsoft Adobe Google but did not hear back or was rejected from them apart from that most of the companies I applied to directly via Careers Page and this was the case with Amazon. I receive the OA link, now since I have signed NDA I won’t give exact problems but will give as close as possible:
OA Round 1: HackerRank. 2 Questions of medium difficulty level to be solved in 60 minutes. I had to write code as well as explain the approach.
- Given an array, return the index of the pair in the array whose sum is K. If there is more than one pair, return the index of the pair which has the biggest individual element.
- A book is represented by a Binary string having two types of pages, ‘0’ is an ordinary page, and ‘1’ is bookmarked page. Find the number of ways to select 3 pages in ascending index order such that no two adjacent pages are of the same type.
- There were some behavioral questions as well. And some MCQ questions on Workstyle.
- I was able to solve both questions and pass all TCs. I got a mail that I cleared it and some prep material and was told that my interview would be scheduled in 3 weeks.
I did my prep, and around 4 weeks passed no interview was scheduled I reached out to my recruiter. He/She called me saying can u come for onsite since online it will take a lot of time, I was hesitant but did not want to leave without trying so I decided to attend { had to come from my hometown current job is remote to Bangalore on my expenses around 3000 km}.
Round 2 {Onsite all rounds from hereon are Duration 1 hour }: Taken by Sde-2 having 4 years of exp. He started with my introduction and asked which part of my current job I liked and disliked and then went on to Coding Questions:
- First Question Similar/slight variation of- https://www.geeksforgeeks.org/boundary-traversal-of-binary-tree/amp/
- Second Question variation to- https://www.geeksforgeeks.org/symmetric-tree-tree-which-is-mirror-image-of-itself
I was asked to write code on a piece of paper and it should cover all Tcs and be of production quality. The trick is to be in continuous communication with the interviewer explain your thoughts and make it an interaction instead of an interview, they are there to help most people like that and us. I was able to code the first question optimally but in the second I could see the interviewer wanted something more optimal alas I ran out of time.
Since I had goofed up an easy question I was expecting I may be rejected but not to be.
Round 3{Duration 1 hour 15min}: Taken by an SDE-3 having 6-7 years of experience. He went straight to questions after brief introductions, I sensed that he got feedback to do that based on my first round. The list of questions asked was:
- Median of 2 sorted arrays of same/different size. https://www.geeksforgeeks.org/median-of-two-sorted-arrays-of-different-sizes/amp/
- Add 2 numbers represented by the linked list https://leetcode.com/problems/add-two-numbers/
- Questions on String Manipulation based on certain criteria I am not able to find something similar to that { approach used in my solution used string stream getline stop etc}
- The question which is a variation of the Longest Common Subsequence
He was experienced in C programming and I had that on my resume so he asked me about malloc calloc heap and stack memory
I was able to answer all his questions and code on paper with proper communication, I would like to add that this person was extremely helpful and was suggesting approaches hints, etc. He was really satisfied with my interview and told me the same I asked some questions about Amazon Culture etc to him in the end.
Round 4 { Duration 1 hour 10 min }: Taken by Hiring Manager who is an SDM having 8 years of experience. He asked about my experience in the first 2 rounds and started asking me about my projects in my current company. He went pretty deep in it. Questions were about my Current Team structure, my specific tasks, how I plan them, times when I missed the deadline, time when I disagreed with the manager, and so on. I answered all questions using the Star method and keeping in mind Amazon LP principles { these are very very important}.
He then shifted to questions on Operating systems again he went in-depth on Semaphores, Deadlocks, Race Condition, Memory Allocation, Virtual Memory, Thrashing, etc { Sachin Bansal playlist is a good resource for this }, post that he asked me questions on OOPS asking both real life and code examples on this { such as Virtual Function, Inheritance, Polymorphism, etc }. He tried to ask about System Design Principles but since I had no idea about that I told him that and he moved on.
At least he asked about coding questions he was only interested in knowing my approach and did not ask me to code time left was also not much.
Similar to https://www.geeksforgeeks.org/sliding-window-maximum-maximum-of-all-subarrays-of-size-k/amp/
Based on KMP String Matching algo. I did the traditional dance from brute force-> optimized for both.
At last, I asked him questions on Qualities of Successful SDE in Amazon and correct motivations to work with, etc.
Round 5 {Bar Raiser Duration 1 hour}: Taken Post Lunch/evening which was provided by Amazon by SDM from a different team having 12 years of experience. This round was solely focused on LP and here my experience of working helped me since most of my stories were real and I could go in-depth in them. { Prepare stories on LP principles beforehand and don’t repeat them}. He went completely in-depth pointing out a small inaccuracy in stories I don’t remember all questions but here are a few:
- The time when you took the initiative and it went wrong how did u handle it
- The time when you receive direct praise from your manager or customer
- The time when you failed a deadline
- The time when you innovated something
- The time when you improved an internal process in your team that helped others
- The time when you took ownership of a product/feature
- The time when you worked extra { weekends etc} to complete a task and why was this needed.
- Again use the trusted STAR method, plus add your Learning so STARL ;). Please give at least 2-3 days for it because many people who had better interviewees than me were rejected in this round. This round is key to selection. Keep your stories real as long as possible or pick someone else stories do check that they don’t contradict and practice basic structure beforehand. The interview ended with me asking about the big challenges which amazon is facing now and its main strategy to avoid them.
Result: I was told I am selected 2 days post giving this round.
This community has helped me a lot and thus wanted to write a detailed post.