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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
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- 11
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- 8
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Showing 2161–2190 of 9403 results
- Capital OneMediumSoftware EngineerPrepaid Travel Card Case Study: Checks, Trade-offs, Buggy Filter
A three-part case study on prepaid travel cards: weigh the trade-offs of issuing them, manually check sample numbers against length, Luhn, and prefix rules, then debug Python filter code whose conditionals let invalid numbers through. Tests product reasoning, careful manual rule-checking, and evidence-driven debugging.
Software Engineering FundamentalsOnsitecase-studyvalidationdebugging - Capital OneMediumData ScientistPresent Analytical Process and Recommendations for Credit-Card Profitability.
Evaluates executive communication of credit-card profitability and partnership analysis. Strong answers lead with recommendation, show assumptions and calculations, bring clear artifacts, summarize risks, and drive next steps.
Behavioral & LeadershipHR Screen - Capital OneHardData ScientistPresent and critique an airline delay analysis
This question evaluates a data scientist's skills in time-series feature engineering and seasonality handling, data joining and leakage detection, hierarchical effects at route and airport levels, model selection (regression vs classification), metric choice, time-aware cross-validation, visualization critique, and experiment/KPI design.
Analytics & ExperimentationTechnical Screen - Capital OneHardData ScientistPresent and defend your data challenge end-to-end
This question evaluates end-to-end data science and machine learning competency, focusing on problem definition, data provenance and schema, exploratory data analysis, baselines and modeling choices, validation and metrics, error analysis, fairness and robustness, productionization, and reproducibility.
Machine LearningHR Screen - Capital OneHardData ScientistPrevent data registration outage and reduce loss
This question evaluates competency in production data reliability, monitoring and alerting, incident response, reconciliation, and cross-functional leadership for analytics pipelines.
Behavioral & LeadershipTechnical Screen - Capital OneHardData ScientistPrioritize six improvements for a favorite app
This question evaluates a data scientist's product-thinking, prioritization, impact-estimation, experimentation design, and risk-mitigation competencies, framed within the Behavioral & Leadership domain and focused on product management, modeling, and experimentation.
Behavioral & LeadershipOnsite - Capital OneMediumSoftware EngineerProject Stories on Teamwork, Conflict and Failure for a New-Grad Behavioral Round
A new-grad behavioral round built on stories from your own projects, covering teamwork, a conflict with a teammate or stakeholder, and a failure, each told in Situation, Task, Action, Result form. It tests personal ownership, how you handle disagreement and whether you learn from your mistakes.
Behavioral & LeadershipOnsite - Capital OneMediumData ScientistQuantify and Model Flight Delays Using Statistical Tests
Evaluates flight-delay quantification, modeling, and mitigation testing using historical operational data. Strong answers define delay metrics, model delay probability and severity, avoid leakage, and design valid experiments.
Statistics & MathOnsite - Capital OneMediumData ScientistQuantify and optimize team-match funnel
This question evaluates a data scientist's skills in analytics and experimentation design, focusing on funnel metric definition, conversion and timing analysis, and A/B test planning within the Analytics & Experimentation domain.
Analytics & ExperimentationOnsite - Capital OneMediumData ScientistQuantify database bug cost/benefit
This question evaluates a candidate's ability to perform cohort-based financial impact analysis and basic statistical arithmetic to quantify revenue and cost deltas caused by registration-state errors.
Statistics & MathTechnical Screen - Capital OneMediumSoftware EngineerReason About and Validate Virtual Card Transactions
Implement a policy validation engine for encoded virtual card numbers against incoming transactions, handling rule parsing, Luhn checksum verification, and structured status reporting.
Software Engineering FundamentalsOnsiteStringsValidationClean Code - Capital OneMediumProduct ManagerRecommend Build vs Buy for Restaurants
Solve a build-versus-buy PM case for a restaurant website builder. Covers segmentation, monetization, per-customer profitability, external reservation integration versus in-house build, adoption-adjusted profit, and strategic tradeoffs.
Product / Decision MakingOnsite - Capital OneMediumData ScientistReconcile ledgers with SQL/Python and late events
This question evaluates a candidate's ability to implement data reconciliation and ETL engineering skills, including SQL window functions and joins, time-based FX rate lookups, matching logic for late-arriving events, idempotent daily pipeline design with deterministic keys and exactly-once semantics, and basic statistical charting in Python.
Data Manipulation (SQL/Python)Technical Screen - Capital OneMediumProduct ManagerRedesign the DMV Experience
Redesign the DMV customer experience with a product discovery framework. Covers pain points, problem statement, pre-visit readiness flow, storyboard, metrics, pilot plan, accessibility, and operational tradeoffs.
Product Design & StrategyOnsite - Capital OneMediumData ScientistRefactor code and enforce robustness
This question evaluates proficiency in code refactoring, robustness, input validation, unit testing, environment specification, and complexity analysis for Python data-processing workflows (pandas), within the Coding & Algorithms domain for Data Scientist roles.
Coding & AlgorithmsOnsite - Capital OneMediumSoftware EngineerRemove nodes with a given value
This problem tests your ability to manipulate singly linked lists, specifically handling edge cases like removing head nodes and reassigning pointers in a single pass.
Coding & AlgorithmsTechnical ScreenLinked ListPointersRecursion - Capital OneHardSoftware EngineerReorder a String by Alternating Its Front and Back Characters
Rearrange a string by taking characters alternately from its front and its back: first, last, second, second-to-last and so on until every character is used once. Tests clean index handling for even and odd lengths and building the result efficiently for long inputs.
Coding & AlgorithmsOnline Assessment - Capital OneMediumSoftware EngineerReorder a String by Alternating Its Left and Right Ends
This problem tests string manipulation, two-pointer logic, and the ability to efficiently manage index traversal in both directions simultaneously.
Coding & AlgorithmsOnline AssessmentTwo PointersStringsAlgorithms - Capital OneMediumSoftware EngineerResolve Conflict and Set a Team Objective
Tests your ability to resolve technical and interpersonal disagreements constructively and establish measurable, value-driven team objectives.
Behavioral & LeadershipOnsiteBehavioralConflict ResolutionLeadership - Capital OneMediumData ScientistResolve a Mismatch Between Regression and Classification Metrics
Tests your ability to diagnose modeling and metric mismatches in credit risk and fraud scenarios, design proper two-stage architectures, and select evaluation metrics aligned with business decisions.
Machine LearningOnline Assessmentmachine-learningmodel-evaluationregression - Capital OneMediumMachine Learning EngineerReturn all root-to-leaf tree paths
This question evaluates competence with binary tree structures, path enumeration and traversal techniques along with the ability to represent traversal results as formatted strings.
Coding & AlgorithmsOnsite - Capital OneMediumSoftware EngineerReturn the Top Two Teams by Points, Goal Difference, and Tie Breakers
Implement a ranking algorithm to evaluate sports competition matches, compute points, goal differential, and total goals for each team, and return the indices of the top two teams using multi-level tie-breakers.
Coding & AlgorithmsOnline AssessmentSortingHash TableArray - Capital OneEasyData ScientistReview Preprocessing Code and Tests
This problem tests your ability to identify common pitfalls in data science pipelines, specifically concerning data leakage, handling missing values, and software engineering best practices for reproducibility.
Coding & AlgorithmsOnsiteData PreprocessingData LeakageCode Review - Capital OneMediumMachine Learning EngineerRotate matrix and find max lamp coverage
This question evaluates array and matrix manipulation, in-place algorithm design, interval processing (sweep-line) and interval merging skills, testing competencies in algorithm design, complexity analysis, and robust edge-case reasoning within the Coding & Algorithms domain.
Coding & AlgorithmsOnline Assessment - Capital OneMediumData ScientistSegment 500k users into three groups
This question evaluates a candidate's competency in data-driven customer segmentation, expected-revenue modeling, and trade-off analysis between churn risk and monetization.
Analytics & ExperimentationTechnical Screen - Capital OneMediumData AnalystSet a Minimum Sale Price After Audience Loss and Reinvestment
Calculate a show’s minimum sale price using lost audience value and reinvestment profit, then assess a 60-million-dollar offer.
Analytics & ExperimentationTechnical Screen - Capital OneMediumData ScientistSet membership fee under investment constraints
This question evaluates quantitative skills in pricing optimization, constrained investment allocation, and interpretation of willingness-to-pay curves, testing competency in combining economic reasoning with statistical and mathematical modeling.
Statistics & MathHR Screen - Capital OneMediumData ScientistShould Company Launch Vegan Burger Based on Profit Analysis?
This question evaluates unit-economics and quantitative product-launch decision-making skills, focusing on contribution margin metrics, break-even analysis, profit and profit-margin calculations in the Analytics & Experimentation domain for Data Scientist roles, and is primarily a practical application of symbolic and numeric financial modeling with conceptual economic reasoning. It is commonly asked to assess how candidates translate per-unit prices, variable and fixed costs, and observed volumes into go/no-go judgments by reasoning about profitability, required volume targets, and sensitivity to cost or demand trends.
Analytics & ExperimentationOnsite - Capital OneEasyData AnalystShould a Restaurant Partner with Groupon?
This question evaluates a candidate's competence in unit economics, break-even and profitability modeling, and the ability to distinguish incremental versus cannibalized customers when assessing voucher-based promotional partnerships, reflecting skills in revenue modeling, cost accounting, and business analytics.
Analytics & ExperimentationTechnical Screen - Capital OneMediumSoftware EngineerSimulate Rot Spreading Through an Orchard Grid Over a Number of Days
A grid simulation question about an orchard of rotten trees, healthy trees and empty ground, where each day rot spreads at once from every rotten tree to the healthy trees directly beside it. It asks for the orchard after a given number of days and tests simultaneous updates, blocked cells and very large day counts.
Coding & AlgorithmsOnline Assessment
Capital One