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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 6451–6480 of 9403 results
- OpenAIMediumMachine Learning EngineerVectorize One-Nearest-Neighbor and Express It as a Neural Forward Pass
Tests vectorized distance computation in array libraries and the mathematical equivalence between nearest-prototype classification and an affine neural network layer.
Machine LearningTechnical Screenvectorizationnearest-neighborslinear-algebra - OpenAIHardSoftware EngineerWhy OpenAI, Your View on AGI and AI Safety, and Why You Are Leaving Your Role
Behavioral questions asked by both the recruiter and the hiring manager at a frontier AI lab: why you want to join this company specifically, your views on artificial general intelligence and AI safety, and why you are leaving your current role. It tests specificity, considered views on AI risk and a consistent story.
Behavioral & LeadershipOnsite - OpenAIHardSoftware EngineerWildfire Grid: Days Until Quiet with Expiring Firebreaks
Simulate a wildfire spreading through a forest grid to find how many days until it stops spreading, then extend the model with fire-resistant trees and firebreaks that only hold for a limited number of days before the protected tree becomes flammable.
Software Engineering FundamentalsOnsitebfsgraphssimulation - OpenAIHardData ScientistWrite SQL for repeat churn
This question evaluates proficiency in event-time analytics and cohort churn metric computation using SQL, focusing on correct identification of first qualifying events and aggregation by experimental variant.
Data Manipulation (SQL/Python)Technical Screen - OpenAIMediumData ScientistWrite SQL to compute signup and retention lift
This prompt evaluates SQL proficiency in time-windowed cohort analysis, event deduplication, date arithmetic, and per-variant aggregation for A/B experiments, categorized under Data Manipulation (SQL/Python) and targeted at an intermediate-level Data Scientist role.
Data Manipulation (SQL/Python)Technical Screen - OpenAIMediumSoftware EngineereSIM Data Wallet with Expiring Bundles and Late Usage Records
Implement a prepaid data wallet where usage draws from the soonest-expiring bundle first and records arrive out of timestamp order, then add checkpointing so balance queries do not replay the full history. Tests event-sourced thinking, heap-based priority consumption, and cache invalidation.
Software Engineering FundamentalsOnsiteheapevent-sourcingout-of-order - OpendoorMediumBackend EngineerDesign Map-Based Home Search
This problem tests the ability to design a geo-spatial search service capable of handling high-frequency map interactions, filtering, and data consistency at scale.
System DesignTechnical ScreenGeo-spatialCachingScaling - OpendoorHardBackend EngineerExecute a TTL Key-Value Store with Transactions
This problem tests the implementation of an in-memory key-value store supporting TTL expiration, atomic transactions with rollback capabilities, and logical time-based validation.
Coding & AlgorithmsTechnical ScreenHashMapsTransactionsTTL - OptiverHardData ScientistAnalyze EV, arbitrage, and bet sizing across games
This question evaluates proficiency in probability and statistics—particularly expected value and variance computation, arbitrage detection across payoff tables, quantitative bet-sizing strategies (e.g., Kelly and fractional sizing), and numerical approximation skills for independent discrete outcomes.
Statistics & MathTechnical Screen - OptiverHardSoftware EngineerAnalyze an Unfair-Coin Bankroll Game
This problem tests probability theory and expected value calculations in the context of a game with an unfair coin and a bankroll constraint.
Statistics & MathTechnical ScreenProbabilityExpected ValueRecurrence Relations - OptiverHardSoftware EngineerAnswer why SWE and why Optiver
This prompt evaluates behavioral and leadership competencies within the software engineering domain for low-latency or real-time systems, focusing on motivation, role fit, communication, self-awareness, and interest in trading/financial markets.
Behavioral & LeadershipOnsite - OptiverMediumSoftware EngineerBuild and Validate a Binary Tree from Parent-Child Pairs
This question evaluates understanding of tree and graph concepts, strict string parsing and validation, duplicate and cycle detection, and the construction of canonical S-expressions within the Coding & Algorithms category.
Coding & AlgorithmsOnline Assessment - OptiverMediumSoftware EngineerCalculate Days Between Arbitrary Gregorian Dates
This problem tests the ability to implement a calendar-based calculation algorithm, specifically handling leap year logic and modular arithmetic without iterating through every day.
Coding & AlgorithmsOnline AssessmentAlgorithmsMathCalendar - OptiverHardSoftware EngineerCalculate the Probability That Two Dice Sum to Seven
This question tests fundamental understanding of discrete probability, combinatorics, and the impact of conditional dependencies on outcomes.
Statistics & MathTechnical ScreenProbabilityCombinatoricsStatistics - OptiverHardSoftware EngineerCargo Order Allocation Across Departing Planes
This question evaluates competence in deterministic resource allocation, stateful simulation, and capacity-management under time constraints, exercising algorithmic reasoning and data-structure handling within the Coding & Algorithms domain.
Coding & AlgorithmsTechnical Screen - OptiverMediumSoftware EngineerCompare common data structures and uses
Compare common data structures and uses evaluates algorithm design, data structures, correctness, complexity, edge cases, and implementation details in a realistic interview setting. A strong answer states assumptions, handles edge cases, explains trade-offs, and shows how to validate the result clearly.
Coding & AlgorithmsTechnical Screen - OptiverMediumQuantitative TraderCompare two programs for equivalence
This question evaluates program-equivalence reasoning skills, including understanding of language semantics (mutation, ordering stability, integer overflow/underflow, integer-division behavior), competency in comparing time and space complexity, and the ability to design property-based tests and edge cases.
Coding & AlgorithmsOnline Assessment - OptiverMediumSoftware EngineerCompute expectations, conditionals, odds, and distributions
This question evaluates proficiency in fundamental probability and statistics concepts — including expected value and variance, conditional probability, discrete arrival modeling, betting odds and the Kelly criterion, and combinatorics for draws without replacement — and is categorized under Statistics & Math.
Statistics & MathTechnical Screen - OptiverMediumData ScientistCompute expected coin flips to meet on octagon
Compute expected coin flips to meet on octagon evaluates statistical assumptions, formulas, estimation strategy, uncertainty, edge cases, and interpretation in a realistic interview setting. A strong answer states assumptions, handles edge cases, explains trade-offs, and shows how to validate the result clearly.
Statistics & MathTechnical Screen - OptiverMediumSoftware EngineerCompute negative-price probability after n steps
This question evaluates understanding of discrete probability distributions and random-walk processes within Statistics & Math, testing skills in binomial modeling and numeric computation for probabilistic outcomes.
Statistics & MathOnline Assessment - OptiverMediumQuantitative TraderCompute odds under time pressure
This question evaluates probabilistic reasoning and combinatorial calculation skills, including conditional probability, distributional thinking and the ability to convert probabilities into odds.
Statistics & MathOnline Assessment - OptiverEasySoftware EngineerCompute permutations with repeated letters
This question evaluates combinatorics and counting principles within the Statistics & Math domain, focusing on permutations with repeated characters and the generalization to multiple symbol counts.
Statistics & MathOnline Assessment - OptiverEasyData ScientistCompute probabilities and expectations in random processes
This question evaluates proficiency in probability theory, combinatorics, and mathematical expectation through a series of rapid-fire brain-teasers. It tests the ability to set up clean probabilistic models, apply the right technique, and derive exact closed-form answers under time pressure — skills commonly assessed in quantitative and data science interviews.
Statistics & MathOnline Assessment - OptiverMediumSoftware EngineerCount nonnegative buy/sell sequences
This question evaluates combinatorial reasoning and algorithmic analysis by asking for the count of constrained buy/sell sequences, testing competence in counting under constraints and reasoning about sequence invariants.
Coding & AlgorithmsTechnical Screen - OptiverMediumSoftware EngineerCount the Days Between Two Dates
This question evaluates date arithmetic, calendar logic, string parsing, and correct leap-year handling as implementation competencies. It is commonly asked to assess algorithmic correctness and edge-case handling across month, year, and leap boundaries, falls under the Coding & Algorithms domain (date/calendar problems), and targets practical application rather than purely conceptual understanding.
Coding & AlgorithmsOnline Assessment - OptiverMediumSoftware EngineerCourier Drone: Fastest Fixed-Distance Segment From Tick Logs
From per-tick distance logs, find the highest average speed over any time span that covers exactly a target distance, where spans may start and end partway through a tick. Tests prefix sums, linear interpolation, and showing that an optimal span touches a tick boundary.
Coding & AlgorithmsOnline Assessmentprefix-sumsbinary-searchsliding-window - OptiverMediumSoftware EngineerDays Between Two Calendar Dates
This question evaluates proficiency in date and calendar arithmetic, specifically handling varying month lengths, leap year rules, and computing absolute differences between dates.
Coding & AlgorithmsOnline Assessment - OptiverMediumSoftware EngineerDecide and implement DP/heap and approximation
This question evaluates dynamic programming for counting constrained subsequences, priority-heap implementation and API robustness for job scheduling, and heuristic approximation methods for NP-hard selection problems, along with algorithmic complexity analysis.
Coding & AlgorithmsTechnical Screen - OptiverMediumSoftware EngineerDemonstrate task switching and memory strategies
This question evaluates task-switching ability, working-memory management, interference control, and error-recovery strategies—core executive functions involved in rapid stimulus–response mappings.
Statistics & MathTechnical Screen - OptiverMediumSoftware EngineerDesign a Balloon Festival Simulator
This question evaluates proficiency in data structures, event-driven simulation, numerical aggregation of spatially varying fields, and time-based state tracking for mutable entities.
Coding & AlgorithmsOnline Assessment
OpenAI
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