Applied for multiple positions at qualcomm via Employee Referral and Received communication after 3 Weeks.

College - Tier 1 NIT
Current Org - mid-sized product based
Experience- 9 months full time, 3 months internship

Interview Structure:
1 HirePro OA
2 Tech rounds
1 HM Round

HR reached out to me asking for availability for initial tech interview for the very next day but before the interview I also received a test link, connected with her and she told me to attempt that as well and rescheduled my interview by 2 hour which overlapped with the scrum of my current organisation, found this to be very unprofessional.

1st Tech Round (1.25 hrs)

Started with basic pointer based questions, whats and hows of pointers, difference between wild and dangling pointer etc.

Asked me the syntax to allocated memory dynamically in C, (basically using malloc and realloc)

Asked about RAID(0,1,2) , Microprocessors, CISC vs RISC, volatile keyword, memory allocation differences in C and C++....

Asked me to write pseudo-code for a basic parser that'd parse the code into an AST (Only telling him the approach was enough)

CPU Sheduling bottle necks , can we call mutex a binary semaphore? if not then why not ? virtualisation of memory and difference between MMU and CPU.

Questions related to bootstrapping of operating system, A-Z of the stuff that happens to a computer when a peripheral is connected.

Finally he asked me to write working code of inserting a node in a double linked list after a given index.

[Felt this round went well as I answered almost everything and HR contacted me in the evening to schedule the 2nd round the next day on the same time as the previous interview, was Also told that this will be the last tech round]

2nd Tech Round (1.75 hrs)

Started with basic introduction, projects, current organisation/work, some introductory questions related to API etc as I am currently working on an API development project

Asked to explain entire client-server arhictecture, database management, how's nosql different from sql.

Asked me to code an in-memory database to store a lot of data (In trillions) and how'd I approach the trade offs between memory and time.
(I did one mistake here, I straight up coded a time efficient solution using hashmap but he later told me that time was not the issue here but memory was and that I should've clarified this beforehand, coded another solution in linked list and so this took a lot of time which was a negative imo)

Asked about localisation, stack and heap memory, where will a variable be stored if it's uninitialized, Windows uses big or little endian etc

Then he asked me a question which I think was the main reason for my Rejection. He asked to code a demoable solution to visualise a time series chart on a page, it should be rendered on screen, user must be able to zoom in and zoom out etc. I wrote python in my resume so he asked me to code this in python but I forgot libraries that we used for visualisation and told him such. Then he asked me to do this in C++ and I couldn't remember the render function in C++ too so I asked him will a pseudo code be enough and he hesitantly said okay go ahead , but with only 30 min left I could only just tell him the approach (which I think was not accurate) and he again hesitantly said okay fine.

[Kinda knew i screwed that question and thought writing was on the wall, got rejection call the next day]

I would say be prepared for hardware related topics, machine learning and data visualisation part. There was a clear mismatch in the job role and the position i was looking for but no experience is useless and I think i would be better suited for a more software specific role.