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."
Implement an In-Memory File System
Implement an In-Memory File System Design and implement an in-memory hierarchical file system. It starts with an empty root directory and a current wo...
Design a Cash Register with Inventory and Profit Tracking
Design a Cash Register with Inventory and Profit Tracking Design an object-oriented cash-register system that manages inventory, completes sales, and ...
Select Maximum Call Stacks Across Threads
You receive a collection of sampled call stacks. Each sample contains a threadId and an ordered list of frames from root to leaf. Design an algorithm ...
Design an Indexable Deque with O(1) Access
Design a data structure backed by a deque that supports push front, push back, pop front, pop back, and O(1) access by logical index. Explain how an o...
Build a Streaming Markdown Code Fence Parser
Implement a streaming Markdown parser that recognizes inline code spans marked with backticks and fenced code blocks marked with triple backticks. The...
Implement a Time-Aware Banking System
Implement a Time-Aware Banking System Design an in-memory banking component in four increments. It must create accounts, accept deposits, transfer fun...
Evaluate Defensive Testing and Pair Programming
An engineering interview asks you to compare two practices that aim to reduce defects: defensive testing and pair programming. Explain what each pract...
Design a File Searcher With Symbolic Links
Design an in-memory file-system searcher. The file-system graph contains directories, regular files, and symbolic links. A query selects regular files...
Add Nested Begin, Commit, and Abort Semantics to a Shopping Cart
Add Nested Begin, Commit, and Abort Semantics to a Shopping Cart An in-memory shopping cart already supports add(item), remove(item), and a pure disco...
Implement a Multi-Level Recipe Management Service
Implement a Multi-Level Recipe Management Service Design and implement an in-memory recipe manager. A recipe stores a name, an ordered ingredient list...
Find the Bugs in an AI-Generated URL Shortener
This question evaluates a candidate's ability to review AI-generated code for correctness, consistency, and robustness rather than write code from scr...
Find Duplicate Files with a Hand-Written Directory Traversal
Find Duplicate Files with a Hand-Written Directory Traversal Implement a duplicate-file finder starting from a root directory, but do not use a recurs...
Explain Large Memory Allocation, Swap, and C++ Inline Trade-offs
In a low-level C++ interview, explain what happens when a program requests 8 GB of memory on a machine with 4 GB of RAM, and discuss the purpose and d...
Parallelize Blocking API Calls with a Thread Pool
Parallelize Blocking API Calls with a Thread Pool An existing function loops over a list of inputs and calls a blocking API once per input. Replace th...
Design a Threshold-Based Database Partition Rebalancer
Design a Threshold-Based Database Partition Rebalancer You are given database partitions and a size threshold. Oversized partitions should be split in...
Design a Cloud-Provider Upload Adapter
Design a Cloud-Provider Upload Adapter Design a small class layer that lets a backend initiate direct uploads through different cloud storage provider...
Implement a Recoverable In-Memory Key-Value Store
Implement a Recoverable In-Memory Key-Value Store Design and implement a single-process key-value store whose working set is held in memory and whose ...
Plan Eviction and Cleanup for a Production Cache
Plan Eviction and Cleanup for a Production Cache A process-local timed cache is correct for basic puts and gets, but it can still exhaust memory, reta...
Design an Extensible Tax Policy Engine
Design an Extensible Tax Policy Engine You already have a correct evaluator for one progressive-bracket policy. Design the surrounding tax engine so i...
Represent and Evaluate Boolean Predicate Expressions
Design a data structure to represent and evaluate predicates such as abc > 5 and (test < 8 or team > 9). Support comparisons, and, or, parentheses, an...