YOE: 2.5
Position: SDE1(Backend Services - Java) equivalent at a product company
Location: Hyderabad, India
Date: December, 2020Technical Screen Round:
Kth Frequent Element in a Stream
Asked how will I scale if there were 1 billion integers in the stream. Gave a horizontally scalable design which the interviewer was happy with.
I heard back from HR within 2-3 days for my availability for the actual interview rounds. There were 5 interview rounds all were back to back(30mins to 1hr gap in between), 3 Loop rounds, 1 Hiring Manager Round, and one bartender round
1 Loop round
Coding:
- Merge 2 Hashmaps in Java
- https://leetcode.com/problems/linked-list-cycle-ii/
Follow up: why are we moving with steps of 2 in the Floyd's cycle finidng algo. Can we use 3/4/5 steps? Why / Why not? - given a SORTED string, merge adjascent charecters and increment
Input String -> bbbccde
cccde
dde
ee
f
Output -> f
2 Loop Round
- producer - consumer design. I solved using blockingqueue. Follow up: how can we scale this?
- Given 2 BST, find the nodes which have the minimum absolute difference.
100
/ \
20 500
\
30
80
/ \
60 150
/
10
Answer is 20
Can be either of (30, 10) or (100,80)
3 Loop Round
- write singleton(advantages of lazy loading, eager loading and 2 phased locking)
- https://leetcode.com/problems/number-of-islands/
- mouse and maze problem with cheese
cheese can be anywhere, mouse can start from anywhere and there are walls present(can have dead ends) in the maze
get number of paths to cheese - simple design for a webservice
4 Hiring Manager
- why oci(obviously)
- discussion about product, project role
- discussion about module ownerships in current role
- behavioural questions
Design a circular Queue, expose proper api's to iterate queue
and shift entire queue by n spaces(left or right)
interviewer pushed to make it with a fixed size array
didnt allow java collections
Now what will you do if we need dynamic size of queue and your old code is in prod.
Answered that we can create a wrapper on top of current design to create a new container
with 1.5N size or 2X size and then copy
basically wanted to know how java arraylist is dynamic, how heap space is allocated
Wrapper will allow old code to function properly while new functionalities can be used by new components
- internal compilation of java program, types of gc.
- How will you programatically count the number of Objects created of a particular class.
- Discussion about concurrency utils like
blockingqueue, countdownlatch and cyclicbarrier - Discussion about Executor service and Executor framework. Types of threadpools
Fixed tpool, cache tpool - How to decide thread count
- Discussion about java.atomic framework
- How to debug thread dump
- how to identify memory leak
- Write a small pseudo code to compile a java application concurrently. ( Topological sort)
Lot of questions on java, multhreading and concurrency. Probably as I have worked predominantly on these in my current role.
5 Bartender
- any mistake you made and what was impact?
- how do you make frieds with other collegues?
- did work under pressure
- did you take ownership and deliver
- how does daily day look like
- what %time do you work on prod issues
- did you ever scrap some existing module and come up with a new design. why, how?
- how did you connect with a difficult person
- how did you make others feel included in the team
questions along the same lines
When did you first hear about oci?
Coding ->
https://leetcode.com/problems/remove-nth-node-from-end-of-list/
It was a good experience but it was VERY exhausting. Having 5 almost back to back interviews take a toll(some of them were 1.5 hours). After a while, I felt my brain getting slower. Idk maybe its only for me
Compensation: https://leetcode.com/discuss/compensation/968205/Oracle-OCI-or-IC2-or-Hyderabad