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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
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- 546
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- 11
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Showing 3841–3870 of 4616 results
- SoFiHardData ScientistPlan and validate ranking experiment
This question evaluates skills in experimental design and analytics, covering offline counterfactual replay, interleaving and A/B testing, sample-size and power computation, sequential testing and alpha spending, guardrail monitoring and ramp policies, proxy metrics and covariate adjustment, heterogeneous treatment effect analysis, and governance concerns such as p-hacking and Simpson’s paradox within the Analytics & Experimentation domain for Data Scientist roles. It is commonly asked to probe proficiency in rigorously validating ranking changes while balancing statistical error, operational risk and bias mitigation, and it emphasizes practical application of applied statistical concepts and experiment governance rather than purely theoretical understanding.
Analytics & ExperimentationTechnical Screen - SoFiEasySoftware EngineerReturn All Nodes Reachable from a Starting Vertex
This problem tests your ability to perform a graph traversal (BFS or DFS) to identify all reachable nodes from a specified starting point in an undirected graph.
Coding & AlgorithmsTechnical ScreenGraphsBFSDFS - SoFiHardSoftware EngineerScale a key-value store with consistent hashing
Scale a key-value store with consistent hashing evaluates requirements, scale assumptions, API/data design, architecture, trade-offs, failure modes, and rollout in a realistic interview setting. A strong answer states assumptions, handles edge cases, explains trade-offs, and shows how to validate the result clearly.
System DesignTechnical Screen - SocureHardSoftware EngineerImplement a Concurrent Payment Queue with Visibility Timeouts
Implement a thread-safe in-memory payment queue supporting atomic message consumption, visibility timeouts, receipt-handle validation to prevent stale ACKs, and idempotent submissions.
Software Engineering FundamentalsTechnical ScreenConcurrencyData StructuresMessage Queues - SonatusHardSoftware EngineerCompute days until a higher reading
This question evaluates proficiency in array processing and the next-greater-element concept, measuring algorithmic reasoning about sequence traversal, comparisons, and managing time/space trade-offs.
Coding & AlgorithmsTechnical Screen - SonatusHardSoftware EngineerDesign a RAG system for vehicle documents
This question evaluates a candidate's ability to design a Retrieval-Augmented Generation system, testing competencies in information retrieval, vector search, document ingestion and chunking, metadata modeling, citation handling, security, observability, and scalability within the system design and NLP/information-retrieval domain.
System DesignTechnical Screen - SpacexEasySoftware EngineerAlign Telemetry Streams and Publish Versioned Corrections
Define telemetry subtraction semantics, handle missing or repeated timestamps, and reconcile late events with versioned, idempotent corrections.
Software Engineering FundamentalsTechnical Screen - SpacexEasySoftware EngineerDebug Missing Output from a Python Multiprocessing Pool
Diagnose and fix issues in a Python multiprocessing script where asynchronous workers fail to produce output, addressing pool lifecycle management, exception propagation, and centralized file I/O.
Software Engineering FundamentalsTechnical Screenpythonmultiprocessingconcurrency - SpacexMediumMachine Learning EngineerDiagnose a Production Classifier and Defend Its Systems Design
This problem tests the ability to diagnose training-serving skew in machine learning models and the architectural considerations required to maintain consistency between offline evaluation and online production environments.
Machine LearningTechnical ScreenMLOpsSystem DesignTraining-Serving Skew - SpacexMediumSoftware EngineerDynamic Island Counts
Report the exact island count after each land addition by tracking only activated cells and merging distinct neighboring components efficiently.
Coding & AlgorithmsTechnical Screen - SpacexMediumResearch ScientistImplement and Benchmark Speculative Decoding
Implement autoregressive and speculative decoding algorithms with key-value cache management, along with a benchmarking harness to measure acceptance rates, latency, and throughput.
Machine LearningTechnical ScreenSpeculative DecodingLLM InferenceBenchmarking - SpotifyMediumBackend EngineerLongest Contiguous Stretch of Distinct Characters in a String
A Spotify backend technical-screen coding problem: given a string, find the length of the longest contiguous substring in which no character repeats. It tests careful string scanning, linear-time reasoning, and edge cases such as case sensitivity, ties and empty input.
Coding & AlgorithmsTechnical Screen - SpotifyEasyMachine Learning EngineerQuery Top Played Tracks Globally And By Country
Tests writing clean SQL queries with aggregations, window functions, and deterministic tie-breaking to extract top playback metrics globally and per country.
Data Manipulation (SQL/Python)Technical Screensqlwindow-functionsaggregation - Sprinter HealthMediumSoftware EngineerDesign a Game Store with Purchases, Downloads, and Reviews
Design connected game-store pages for category browsing, purchases, authorized downloads, and reviews with consistent data and retry behavior.
System DesignTechnical Screen - SquareHardSoftware EngineerImplement transaction network queries
This question evaluates the ability to model and query dynamic graph connectivity and reachability for pairwise transactions, testing competencies in graph representation, dynamic data structures, and reachability queries within the Coding & Algorithms domain and emphasizing practical application of algorithmic concepts.
Coding & AlgorithmsTechnical Screen - SquareEasySoftware EngineerList the Two-by-Two Blocks Covering Each Black Cell
This problem tests your ability to navigate grid coordinates, implement range boundaries, and perform efficient dictionary-based data collection.
Coding & AlgorithmsTechnical ScreenArraysHash MapsGrid - SquarepointHardData ScientistAnalyze expectations, correlations, and investment strategies
This problem tests your understanding of stochastic processes in finance, the linear algebraic requirements for covariance matrices, and optimal decision-making under uncertainty.
Machine LearningTechnical ScreenProbabilityLinear AlgebraStochastic Calculus - SquarepointMediumQuantitative ResearcherChoose Between an Array and a Linked List
Tests understanding of arrays versus linked lists beyond asymptotic Big O notation, focusing on CPU cache locality, memory layout overhead, reference stability, and practical queue design.
Software Engineering FundamentalsTechnical Screendata-structurescache-localitymemory-hierarchy - SquarepointMediumData ScientistCompare Bonds, Common Equity, and Dividend Payments
Compare debt and common equity claims, cash flows, risks, and why company profits do not guarantee common-share dividends.
Statistics & MathTechnical Screen - SquarepointMediumData ScientistCompare Winning Chances in a Card Game That Replays Ties
Use symmetry and tied-round replay to compare two players drawing cards without replacement and derive the game's eventual winning probabilities.
Statistics & MathTechnical Screen - SquarepointMediumData ScientistCompute drawdown, profit, and coin change
This question evaluates a candidate's ability to compute financial time-series metrics and apply algorithmic techniques such as array processing and optimization/dynamic programming to identify maximum drawdown and its indices.
Coding & AlgorithmsTechnical Screen - SquarepointMediumRisk Technology Software EngineerConcatenate Two C++ Index Sequences at Compile Time
This problem tests your mastery of C++ variadic templates, template metaprogramming, and the `std::index_sequence` utility to perform type-level list manipulation.
Software Engineering FundamentalsTechnical ScreenC++TemplatesMetaprogramming - SquarepointMediumQuantitative ResearcherCount Files Safely from Bash
Tests command-line proficiency and Bash scripting fundamentals by requiring a robust mechanism to count regular files across a directory tree while handling tricky filenames, symlinks, and recursion correctly.
Software Engineering FundamentalsTechnical Screenbashlinuxshell-scripting - SquarepointMediumData ScientistCount Index Triplets With an Even Product Modulo a Given Number
From a Squarepoint technical screen: count the triplets of distinct positions in an integer array whose three values have an even product, and return the count modulo a given number. It tests efficient counting on large inputs, parity with zero and negative values, and remembering to apply the required modulo.
Coding & AlgorithmsTechnical Screen - SquarepointMediumData ScientistCount Ways to Reach Step n With a Given Set of Step Sizes
From a Squarepoint technical screen: count the ordered sequences of moves that climb exactly n stairs when every move uses a step size from a given set. It tests careful counting of ordered choices, targets that cannot be reached, and the interviewer's follow-up about reducing the extra space the solution uses.
Coding & AlgorithmsTechnical Screen - SquarepointMediumRisk Technology Software EngineerDesign an Ordered Vector with Move Semantics and Analyze Its Memory Layout
This problem tests your understanding of C++ memory management, template programming, exception safety, and the performance implications of different data storage strategies.
Software Engineering FundamentalsTechnical ScreenC++Memory ManagementTemplates - SquarepointMediumData ScientistEstimate Market Beta from Aligned Asset and Benchmark Returns
Define market beta, identify the benchmark data needed beyond a stock's returns, and explain regression estimation and uncertainty.
Statistics & MathTechnical Screen - SquarepointMediumSoftware EngineerEvaluate Linear Regression Assumptions and Fit Three Points
Discuss the assumptions behind ordinary least squares, how multicollinearity affects a fitted model, and practical ways to address multicollinearity and overfitting. Cover data and labels, leakage-safe features, baselines and model choice, offline evaluation, deployment constraints, monitoring, and drift.
Machine LearningTechnical Screen - SquarepointMediumData ScientistExplain Linear Regression Assumptions, Evaluation, and Feature Addition
Explain least-squares regression, inference assumptions, evaluation metrics, and why added features affect training and test R-squared differently.
Machine LearningTechnical Screen - SquarepointMediumRisk Technology Software EngineerExplain Low-Latency Linux Networking and Shared-Memory Trade-Offs
Assess the candidate's understanding of low-latency Linux systems, comparing network socket tuning, kernel-bypass stacks, and lock-free shared memory along with NUMA and observability considerations.
Software Engineering FundamentalsTechnical ScreenLinuxLow LatencyNetworking
SoFi
Spotify
Square
Squarepoint