Role: Senior Engineer (Display team)
College: Not Specified (3.2 years of experience as SDE 2)
Interview Date: March 2024
Interview Type: Off-Campus (Applied through career page)
Result: Offer
Difficulty: Not Specified
Rounds: 3 rounds (No written or online assessments)
Topics Asked: C/C++ Fundamentals (Processes, Threads, Dangling Pointers, Polymorphism, Virtual and Friend keywords), Code output/errors, Data Structures & Algorithms (Merge k sorted lists), Low-Level Algorithmic Design (Producer-Consumer problem with CRT display and SoC chipset), Behavioral/Puzzles (Door Flip Puzzle, Divisibility Rule of 11).
Experience:
This candidate, with 3.2 years of experience as an SDE 2, interviewed for a Senior Engineer position in Qualcomm's Display team in March 2024 and received an offer in April 2024. The process moved swiftly with no written assessments.
Round 1: Coding (1 hour 10 minutes)
- Introductions and discussion about current work and projects (10 minutes).
- Technical Discussion (45 minutes): Fundamental C++ and C concepts, including processes, threads, dangling pointers, polymorphism (types, examples, code samples), virtual and friend keywords.
- Technical discussion involved MCQ-style questions on code output, compilation, and runtime errors.
- Coding Challenge: Merge k sorted lists. The entire solution was written on a shared whiteboard, followed by time complexity analysis and a code walkthrough.
Round 2: Design (2 hours 5 minutes)
- Introductions and detailed discussion of current work and projects (20 minutes).
- Low-Level Algorithmic Discussion (1 hour): Scenario involving a CRT display panel and an SoC chipset sharing a single memory buffer (SoC writes next frame as producer, panel reads as consumer). Assumed 120 FPS and 1ms turnaround time. The problem involved displaying frames line by line and a scenario where a previous frame showed "A" and the current frame showed "B" (detailed discussion on this scenario).
Round 3: Hiring Manager (25 minutes)
- Introductions.
- Puzzles/Behavioral:
- Door Flip Puzzle: Given N doors, all initially closed. N people (1 to N). Person 1 flips all doors that are multiples of 1. Person 2 flips all doors that are multiples of 2, and so on. Person N flips all doors that are multiples of N.
- Divisibility Rule of 11: Task was to explain the divisibility rule of 11.