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 a Simple Memory Allocator
Design and implement a simplified memory allocator exposing malloc(size) and free(ptr) over a single fixed-size heap (a contiguous byte array). The al...
Design Calendar Event CRUD with Unit Tests
Design and implement a small calendar application that supports creating, editing, and deleting events. The interviewer expects unit tests and clean s...
Parse a CSV and Generate a Gift Exchange
Parse a CSV and Generate a Gift Exchange Implement a small gift-exchange service. The input is CSV text with headers name,email. Parse valid participa...
Explain C++ Inline, Segfaults, Virtual Memory, and std::string Internals
Answer a C++ systems interview covering inline functions and inline variables, segmentation faults, MMU address translation, TLB and page tables, page...
Defend a Redis Choice and Explain Database Index Trade-offs
Defend a Redis Choice and Explain Database Index Trade-offs During a project deep dive, an interviewer asks why your system used Redis and whether the...
Prove an Incremental Shuffle Is Uniform
Prove an Incremental Shuffle Is Uniform Consider this in-place shuffle for an array of length n: `text for i from 0 through n - 1: j = a uniformly...
Find Bugs in an LRU Cache
Find Bugs in an LRU Cache The Java class below is intended to implement a least-recently-used cache. A successful get and every put should make the ke...
Find the Most Frequent IP Addresses in a File Too Large for Memory
Design an exact, bounded-memory method for finding the most frequent IP addresses in a file far larger than RAM. Analyze memory and disk-I/O trade-off...
Wrap a Fixed-Chunk Stream Reader with Arbitrary-Length Reads
You are given a low-level stream API that reads exactly 4096 bytes at a time. Design a wrapper API read(n) that returns any requested number of bytes,...
Navigate a Maze Through a Next-Step API
You are given an API that returns the next location you should visit in a maze. Starting from an initial location, repeatedly call the API until you r...
Compare Quicksort and Mergesort in Practice
Compare Quicksort and Mergesort in Practice Compare Quicksort and Mergesort as choices for sorting a large collection. Explain their mechanics, comple...
Sort One Hundred Million Digits
Sort One Hundred Million Digits You must sort an unsorted collection of 100,000,000 integer digits, each in the range 0 through 9. Describe an algorit...
Design a Real-Time Top-K Ranking System
Design an object-oriented, real-time Top-K ranking system. The system continuously receives score updates for a large set of entities — for example us...
Refactor a Chatbot into Clean Object-Oriented Components
Prepare for a OpenAI software engineering interview question about refactor a chatbot into clean object-oriented components. The prompt highlights pra...
Design a Population-Weighted Random Country Picker
Design a Population-Weighted Random Country Picker Design a class initialized with country names and positive population weights. Each call to pick() ...
Explain Lazy Loading and Frontend Code Splitting
Explain Lazy Loading and Frontend Code Splitting A single-page application has grown until its initial JavaScript bundle delays interactivity. Explain...
Reason About Indexes, Kafka, and Database Locking
Reason About Indexes, Kafka, and Database Locking Answer the three backend fundamentals sections below. For each one, connect the mechanism to a concr...
Solve Timed Logical and Quantitative Reasoning Cases
Solve Timed Logical and Quantitative Reasoning Cases Work through the seven short assessment cases below. For each reasoning case, use only the stated...
Explain and Harden Two Shell Commands
Explain and Harden Two Shell Commands Explain the behavior, operator semantics, and failure risks of these shell commands: `sh ps aux | grep foo | gre...
Implement Spreadsheet Cells with Dependencies
Design spreadsheet-like get and set operations for cells where formulas can depend on other cells. When a cell changes, dependent cells should reflect...