Software Engineering Fundamentals Interview Questions
Practice 603 real Software Engineering Fundamentals interview questions for 2026. Covers core coding, data structures, complexity analysis, debugging, and implementation best practices — real questions from actual interviews with detailed solutions to support focused interview preparation. This category tests the engineering basics interviewers rely on to predict on-the-job performance: correct and efficient algorithms, clean and maintainable code, complexity trade-offs, edge-case reasoning, and the ability to turn requirements into a working implementation under time pressure. Expect heavy weighting at companies like Amazon, Google, and OpenAI, where fundamentals often gate candidates before system design or product rounds. To prepare, prioritize timed problem practice that enforces clear communication, complexity justification, and test-case coverage; drill common data structures and complexity patterns until they become second nature; and rehearse coding on a whiteboard or shared editor to simulate real loop conditions.

"I got asked a hardcore MCM DP question and I saw it on PracHub as well. Solved that question in 5 minutes. Without PracHub I doubt I could solve it in 5 hours. Though somehow didn't get hired, perhaps I guess I solved it too fast? /s"

"Believe me i'm a student here jn US. Recently interviewed for MSFT. They asked me exact question from PracHub. I saw it the night before and ignored it cause why waste time on random sites. I legit wanna go back and redo this whole thing if I had chance. Not saying will work for everyone but there is certainly some merit to that website. And i'm gonna use it in future prep from now on like lc tagged"

"10 years of experience but never worked at a top company. PracHub's senior-level questions helped me break into FAANG at 35. Age is just a number."

"I was skeptical about the 'real questions' claim, so I put it to the test. I searched for the exact question I got grilled on at my last Meta onsite... and it was right there. Word for word."

"Got a Google recruiter call on Monday, interview on Friday. Crammed PracHub for 4 days. Passed every round. This platform is a miracle worker."

"I've used LC, Glassdoor, and random Discords. Nothing comes close to the accuracy here. The questions are actually current — that's what got me. Felt like I had a cheat sheet during the interview."

"The solution quality is insane. It covers approach, edge cases, time complexity, follow-ups. Nothing else comes close."

"Legit the only resource you need. TC went from 180k -> 350k. Just memorize the top 50 for your target company and you're golden."

"PracHub Premium for one month cost me the price of two coffees a week. It landed me a $280K+ starting offer."

"Literally just signed a $600k offer. I only had 2 weeks to prep, so I focused entirely on the company-tagged lists here. If you're targeting L5+, don't overthink it."

"Coaches and bootcamp prep courses cost around $200-300 but PracHub Premium is actually less than a Netflix subscription. And it landed me a $178K offer."

"I honestly don't know how you guys gather so many real interview questions. It's almost scary. I walked into my Amazon loop and recognized 3 out of 4 problems from your database."

"Discovered PracHub 10 days before my interview. By day 5, I stopped being nervous. By interview day, I was actually excited to show what I knew."

"I recently cleared Uber interviews (strong hire in the design round) and all the questions were present in prachub."
"The search is what sold me. I typed in a really niche DP problem I got asked last year and it actually came up, full breakdown and everything. These guys are clearly updating it constantly."
Design article voting and flip-tracking system
This question evaluates object-oriented design, stateful data modeling, vote aggregation, and time-ordered event history tracking competencies in the ...
From Take-Home Script to Production: Python Trade-offs and Hardening a Data Job
From Take-Home Script to Production: Python Trade-offs and Hardening a Data Job You are in a software-engineering interview at a quantitative trading ...
Design a Ride Scheduler
This question evaluates object-oriented design, event-driven scheduling and simulation, state management for ordered task execution, API design, and h...
Explain Vector, Linked List, and Polymorphism
In a C++ interview, explain the differences between a dynamic array container such as std::vector and a linked-list-based container such as std::list....
How do you perform a thorough code review?
You are given several Python backend files to review (treat this as an “OA in code-review format”). The code performs database operations such as SQL ...
How do you debug slowness and bugs?
The interviewer asked two practical engineering questions: 1. A web application's frontend is loading very slowly. Describe how you would diagnose the...
Debug React Sorting, Persistence, Routing, and Accessibility
Prepare for a HackerRank software engineering interview question about debug react sorting, persistence, routing, and accessibility. The prompt highli...
Explain Runnable vs Callable and thread-safe Singleton
This question evaluates a candidate's knowledge of Java concurrency and design patterns, specifically distinctions between Runnable and Callable, mech...
Build an emoji blaster animation on iOS
iOS "Blaster" App: Press-and-Hold Emoji Projectiles Problem Build a minimal iOS app with a button fixed at the bottom. While the user presses and hold...
Design an API for pay computation with retries
You’ve implemented logic that computes a dasher’s pay from order event logs (events include timestamps and state transitions). Design an HTTP API to e...
What are processes vs threads?
Question Explain the difference between multiprocessing and multithreading in the context of building concurrent applications. Cover the following: - ...
Design a mini compiler/interpreter
Problem Design and implement a mini compiler / interpreter for a small expression language. You are given a program as a string (possibly multiple lin...
Optimize a dispatcher’s scheduling data structures
Algorithmic analysis / code review: Dispatcher for memory-constrained scheduling You are given a single-threaded in-memory dispatcher that reacts to t...
How would you improve AI-generated code?
During a pair-programming interview, you wrote the rover simulator code using an AI coding assistant. The code works for the basic examples, but the i...
Find largest file in a directory using Bash
This question evaluates a candidate's proficiency with shell scripting and Unix command-line concepts, including recursive file-system traversal, reco...
Implement a Connection Pool
You are given an existing DBConnection class that simulates a physical database connection. It exposes the following methods and must not be modified:...
Design an Extensible Python File Parser
This question evaluates skills in designing extensible, modular file-parsing frameworks in Python, covering interface and API design, format detection...
Explain what happens when you run ls
In Linux, explain the end-to-end flow of what happens when a user types ls in a shell and presses Enter. Include: - What the shell does - How the exec...
Explain sync/async, Go concurrency, SQL vs NoSQL
You are interviewing for a backend engineering role. Answer the following conceptual questions clearly and with concrete examples. 1) Synchronous vs a...
Reason About CPU Microarchitecture and Simulator Design
Reason About CPU Microarchitecture and Simulator Design Answer the following systems questions for a modern out-of-order CPU. State architectural assu...