Software Engineer Interview Questions
Practice 4,429 real software engineer interview questions for 2026. Covers top employers like Google, Amazon, OpenAI, and Uber — real questions from actual onsites with detailed solutions — and is built for focused interview preparation. This collection emphasizes coding and algorithms first, then system design, performance, and role-specific domains so you can train the exact skills interviewers test. What’s distinctive: coding rounds still dominate at every company, Google often emphasizes algorithms and distributed-systems thinking, Amazon commonly probes scalable-services design and operational tradeoffs, OpenAI leans toward ML systems, model deployment and inference-scaling problems, and Uber typically asks real-time routing, geospatial and consistency challenges. Expect live coding, pair-programming, and whiteboard/system-design sketches. To prepare efficiently, drill medium-to-hard algorithm problems with time limits, practice end-to-end system design sketches focused on capacity and reliability, and rehearse concise behavioral stories that show ownership and impact.
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"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."
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"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."
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"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."
Produce valid student lineup from parent array
You are given a hierarchy of n students represented by a parent array par of length n. - Students are labeled 1..n. - par[i] is the parent (mentor/man...
Answer suffix maximum-frequency queries
You are given: - An integer array nums of length n. - An integer array queries of length m, where each queries[k] is an index i (0-based) into nums. F...
Decompress encoded string with nested repeats
Given an encoded string, decompress it into its expanded form. Encoding rules: - Parentheses (...) denote a group. - A repetition count is written in ...
Compute iterative sliding-window sum reduction
Problem Given an integer array nums and an integer window size k, repeatedly apply the following reduction: - If len(nums) > k: replace nums with a ne...
Explain learning paradigms, loss, and embeddings
ML fundamentals (oral) Answer the following conceptual questions clearly and with examples: 1. What is supervised learning? What are typical inputs/la...
Solve string and hashmap coding tasks
You will solve the following coding tasks (independent of each other). Provide clear input/output behavior and handle edge cases. 1) Longest non-repea...
Can you visit all rooms and score parentheses?
Problem 1: Visit all locked rooms with keys There are n rooms labeled 0..n-1. All rooms are locked except room 0. - When you enter room i, you find a ...
Compute maximum later-earlier difference
You are given an integer array output (length n ≥ 1). Define the gain of choosing indices i < j as output[j] - output[i]. Return the maximum gain over...
Design dynamic weighted random sampling with updates
Problem: Support weighted random sampling with insert/delete Design a data structure that maintains a dynamic set of items, each with a positive integ...
Solve common interview coding problems
You are given several independent coding tasks (typical of SWE/MLE interview rounds). For each task, design an algorithm and describe the time/space c...
Design iterator for sorted union
Problem: Union Iterator for Sorted Inputs You are given two input iterators it1 and it2. Each iterator returns integers in strictly increasing order (...
Compute sums and maximum path in a tree
You are given a binary tree whose nodes store integer values. You must implement your own Node class (e.g., val, left, right). Task Write a function t...
How to handle huge inputs?
In a coding interview, after solving an in-memory algorithmic problem, the interviewer asks: "What would you do if the input were extremely large?" Gi...
Solve substring and access-log problems
The interview included the following coding tasks: 1. Longest uniform substring after limited changes Given a string s consisting of uppercase En...
Design a global notification service
Design a global notification service System Design: Globally Distributed Notification Service Context You are designing a multi-tenant notification pl...
Implement topological sort from string input
You receive N lines of raw text describing task dependencies, e.g., 'install A after B', 'C->A', 'B before D'. Implement a function that: ( 1) parses ...
Design an in-memory database with TTL and backups
You are asked to implement a small in-memory “database” that evolves across 4 parts. In each part you may reuse your previous code and only add/extend...
Design an online real-time chess game
Design an online real-time chess service, similar to chess.com. Users should be able to sign in, use matchmaking, play real-time games, make moves wit...
Parse chemical formula with multipliers
Parse chemical formula with multipliers Given a string representing a chemical formula, parse it and return the total count of each element. The formu...
Design a Real-Time Suggestions Service
Design a Real-Time Suggestions Service System Design: Real-Time Typeahead/Autocomplete Context Design a real-time typeahead/autocomplete service for a...