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Interview Questions
Practice 9403 coding, system design and machine learning questions from 546 companies, sorted by role, topic and interview round. Every question has step-by-step hints, a code runner that supports 8 languages and an AI mentor; members also get the full solution walkthrough.
- 9403
- Questions
- 546
- Companies
- 11
- Topics
- 8
- Languages
Showing 1591–1620 of 3640 results
- Home DepotEasyProduct AnalystDebug SQL join that drops rows
This question evaluates understanding of SQL joins, filtering interactions, aggregation, and troubleshooting data discrepancies when combining sales, sale_items, products, and promotions tables.
Data Manipulation (SQL/Python)Onsite - Home DepotMediumData AnalystDebug row loss after SQL joins
This question evaluates SQL data manipulation and JOIN logic skills, including temporal and timezone-aware date handling and aggregation, within the Data Manipulation (SQL/Python) domain and primarily tests practical application-level competency.
Data Manipulation (SQL/Python)Onsite - Home DepotEasyProduct AnalystDecide whether to keep a negative-margin promotion
This question evaluates proficiency in analytics, experiment design, causal inference, metric definition, and business-impact analysis for a Product Analyst role, including handling noisy cost data and partial customer identifiers.
Analytics & ExperimentationOnsite - Hot Agent StartupMediumSoftware EngineerDesign Flight Booking and Voting Systems
This question evaluates system design competencies including large-scale backend architecture, data modeling and indexing, database internals, concurrency control to prevent overselling, and high-throughput real-time streaming and metrics for live updates.
System DesignOnsite - Hot Agent StartupMediumSoftware EngineerImplement a Thread-Safe Pub-Sub Service
This question evaluates concurrent programming and thread-safety skills within the Software Engineering Fundamentals domain, focusing on synchronization primitives, message delivery semantics, and coordination between publishers and subscribers at a practical application level.
Software Engineering FundamentalsOnsite - HubSpotHardSoftware EngineerDesign a Netflix-like streaming platform
A HubSpot software-engineer onsite system-design question: design a Netflix-like video streaming platform covering catalog browse by genre and curated rails (Recently Added, Top Ten), search, adaptive-bitrate playback across web, mobile and TV, cross-device resume, and an upload-to-streamable ingest pipeline. It evaluates service decomposition, data models and API contracts, transcoding and CMAF/multi-DRM packaging, CDN and caching strategy, session concurrency and consistency, multi-region failover, observability and A/B testing, graceful degradation, and cost control at millions of concurrent viewers. The worked solution sizes egress and heartbeat load, corrects the common concurrency, resume, and cache-TTL mistakes, and marks the MVP cut line.
System DesignOnsite - HubSpotHardSoftware EngineerDesign a near-real-time weather API
A HubSpot onsite system-design question: build a weather data platform that ingests hourly dumps for ~2,000 U.S. locations and serves the current temperature with an at-most-10-minute freshness SLA. It tests ingestion pipelines, idempotent retries and backfill, caching and invalidation, storage modeling, rate-limit handling, scaling, and observability on freshness SLOs.
System DesignOnsite - HubSpotEasySoftware EngineerDesign an hourly weather crawling service
This question evaluates a candidate's ability to design scalable, reliable data ingestion and delivery systems, covering competencies such as scheduling and crawling, data normalization, storage schema design, idempotent ingestion, rate limiting, retries, and monitoring.
System DesignOnsite - HubSpotEasySoftware EngineerFind a special person using knows(a,b)
This question evaluates algorithmic reasoning about pairwise relation inference using an oracle-style knows(a, b) API and the ability to minimize API calls, testing skills in graph modeling and asymptotic analysis.
Coding & AlgorithmsOnsite - HubSpotMediumSoftware EngineerFind spammer with minimal hasMessaged calls
Find the "spammer" account that messaged every other account but received from none, using only a hasMessaged(a, b) oracle. This is the classic find-the-celebrity problem inverted, solved with a two-phase elimination-then-verify algorithm in O(n) oracle calls and O(1) extra space, with full correctness proof and edge-case handling.
Coding & AlgorithmsOnsite - HubSpotMediumFrontend EngineerJavaScript Fundamentals: Prototype Chains and How 'this' Is Bound
A JavaScript fundamentals question that asks you to predict and explain how this is bound in method calls, detached calls, bound functions and arrow functions, trace property lookup through a prototype chain, and rewrite constructor-based inheritance with class syntax. It tests precise reasoning about core language behaviour.
Software Engineering FundamentalsOnsite - Hudson River TradingHardSoftware EngineerBuild a Heart Disease Baseline
This question evaluates proficiency in applied machine learning workflows, including data inspection and cleaning, exploratory data analysis, feature engineering, baseline binary classification modeling, and evaluation using Python libraries like pandas and seaborn.
Machine LearningOnsite - Hudson River TradingMediumSoftware EngineerCompare C++ Virtual Dispatch with CRTP
Compare C++ virtual dispatch with CRTP across runtime flexibility, object layout, separate compilation, heterogeneous collections, inlining, code size, diagnostics, ABI stability, and measured performance.
Software Engineering FundamentalsOnsite - Hudson River TradingEasyMachine Learning EngineerCount People Reaching the Boundary
This question evaluates algorithmic simulation and event-driven modeling skills, specifically handling discrete versus continuous time, visibility constraints relative to a stationary watcher that changes facing direction, and boundary conditions for state transitions.
Coding & AlgorithmsOnsite - Hudson River TradingMediumSoftware EngineerDesign a Fixed-Size Memory Allocator with Correct Alignment
Design a slab-backed fixed-size allocator with constant-time free-list operations, correct stride and alignment, separate object lifetime, corruption defenses, concurrency choices, and efficient handling of nine-byte payloads.
Software Engineering FundamentalsOnsite - Hudson River TradingMediumSoftware EngineerExplain Virtual Memory, MMUs, and TLBs
Trace a virtual-memory load through TLB lookup, page-table walking, MMU permission checks, cache and physical access, page-fault handling, context switches, huge pages, and cross-core shootdowns.
Software Engineering FundamentalsOnsite - Hudson River TradingHardSoftware EngineerImplement Order Modification Feature
This question evaluates a software engineering competency in modifying and extending a C++ client/server trading system, focusing on state management, input validation, API integration, and maintaining invariants for order lifecycle.
Coding & AlgorithmsOnsite - IBMEasySoftware EngineerExplain CI/CD, Kubernetes delivery, and troubleshooting
This question evaluates operational DevOps and cloud-native competencies, specifically CI/CD concepts and tools, GitOps delivery with Argo CD, Kubernetes deployment and troubleshooting (including Helm and StatefulSet vs Deployment), containerization rationale, Linux process and file inspection, network diagnostics, database deployment safety, and infrastructure concepts such as HPC and VPC. It is commonly asked in Software Engineering Fundamentals and DevOps interviews to measure production-readiness, troubleshooting ability, and tooling familiarity, emphasizing practical application while requiring underlying conceptual understanding of system behavior and reliability.
Software Engineering FundamentalsOnsite - IBMEasySoftware EngineerHow would you use generative AI at work?
This question evaluates a candidate's judgment and leadership in applying generative AI tools, testing competencies in risk assessment, data confidentiality, security awareness, correctness verification, and team change management for a software engineer role.
Behavioral & LeadershipOnsite - IllumioMediumSoftware EngineerCount Regions in a Binary Grid
This problem tests your ability to navigate a 2D grid and identify connected components using graph traversal techniques like Depth-First Search (DFS) or Breadth-First Search (BFS).
Coding & AlgorithmsOnsiteDFSBFSGraph - IllumioMediumSoftware EngineerDesign Multicloud Publishing and API Gateway
This question tests the ability to design a distributed system that reliably replicates data from a primary database to multiple cloud providers while exposing a unified, secure API gateway for external consumers.
System DesignOnsiteDistributed SystemsAPI GatewayCDC - IllumioHardSoftware EngineerDesign a Time-Series Database
This problem tests the ability to architect a high-throughput, horizontally scalable system for time-series data, balancing ingest performance with efficient range-query capability.
System DesignOnsiteTime-SeriesDistributed SystemsIndexing - IllumioMediumSoftware EngineerSolve Matrix Traversal and Pair Sum
This problem tests your ability to manipulate 2D matrix indices for spiral traversal and apply efficient hash-based lookups to solve the two-sum problem within a specific sequence.
Coding & AlgorithmsOnsiteMatrixArrayHash Table - ImcEasyHardware EngineerAnalyze an Instruction Trace with Latency, Throughput, Cache, and Roofline Constraints
Implement a pipeline simulation that calculates total execution cycles under RAW data hazards and computes roofline bottleneck metrics for a given instruction trace.
Software Engineering FundamentalsOnsiteComputer ArchitectureHardwareSimulation - ImcMediumData ScientistCompute gambler’s ruin probabilities and hitting times
This question tests your ability to model a discrete random walk as a Markov chain, derive the probability of reaching an absorption state, and calculate the expected time to reach that state.
Machine LearningOnsiteProbabilityMarkov ChainsStochastic Processes - ImcMediumData ScientistExplain linear regression and Transformer fundamentals
This question tests your ability to explain the theoretical foundations of linear regression, including its probabilistic interpretation, and your technical depth regarding the mechanics of the Transformer architecture.
Machine LearningOnsiteLinear RegressionTransformersSelf-Attention - ImcMediumData ScientistRun EDA and train models while preventing overfitting
This problem tests your end-to-end machine learning pipeline skills, focusing on tabular regression, feature engineering, validation strategies, and regularization techniques.
Machine LearningOnsiteRegressionOverfittingEDA - ImcMediumData ScientistSolve a constrained problem using KKT conditions
This question tests the ability to solve a convex optimization problem under inequality constraints using KKT conditions and the identification of active versus inactive constraints.
Machine LearningOnsiteOptimizationKKTCalculus - InstacartHardData ScientistAnalyze A/B test with revenue–cost tradeoffs
This question evaluates a data scientist's skills in experimental design and statistical inference for A/B testing, revenue-impact modeling with skewed and zero-inflated metrics, segmentation for heterogeneous treatment effects, and constrained optimization to balance contribution and operational risk.
Analytics & ExperimentationOnsite - InstacartMediumSoftware EngineerAnswer standard behavioral questions
How to answer the standard behavioral and leadership questions in an Instacart Software Engineer onsite using the STAR framework. Covers tell-me-about-yourself, end-to-end ownership, high-severity incidents, conflict and disagreement, failure and learning, tight deadlines with ambiguous requirements, prioritization, influencing without authority, process improvement, and your most impactful accomplishment — each with a quantified model answer.
Behavioral & LeadershipOnsite
HubSpot
Hudson River Trading
IBM
Imc
Instacart