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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.
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Showing 6481–6510 of 9403 results
- OptiverMediumSoftware EngineerDesign a Multi-Level Expiring Item Store
Design an in-memory multi-level key-value store where items are stored at specific priority levels with individual expiration timestamps, supporting query fallback and expiration cleanup.
Software Engineering FundamentalsOnline AssessmentData StructuresDesignHash Table - OptiverHardSoftware EngineerDesign a News Subscription Processing Engine
Design and implement an in-memory news subscription processing engine that supports attribute-based filtering, deduplication, unsubscription, and unacknowledged delivery tracking.
Software Engineering FundamentalsOnline AssessmentLow-Level DesignPub-SubConcurrency - OptiverMediumSoftware EngineerDesign a balloon stability tracker
This question evaluates event-driven simulation, time-ordered state management, floating-point numerical evaluation of aggregate functions, and data-structure design for tracking dynamic object states and stability thresholds; it falls under the Coding & Algorithms domain, specifically simulation, event processing, and algorithmic data structures.
Coding & AlgorithmsOnline Assessment - OptiverMediumSoftware EngineerDesign a circular queue data structure
This problem tests your ability to implement a fixed-capacity circular queue using a static array, focusing on efficient pointer arithmetic and state management.
Coding & AlgorithmsTechnical ScreenData StructuresArraysQueues - OptiverMediumSoftware EngineerDesign a queue and analyze tradeoffs
This question evaluates understanding of FIFO data structures, algorithmic complexity analysis, memory and cache behavior, and concurrent access concerns.
Coding & AlgorithmsTechnical Screen - OptiverMediumSoftware EngineerDesign a satellite propagation simulator
Optiver software-engineer take-home: implement a SatelliteNetwork that simulates timed message propagation over an undirected graph and fires OnSatelliteReportedBack callbacks in deterministic order. It tests graph modeling, discrete-event simulation, priority-queue scheduling, and careful handling of 10s-per-hop forwarding and 30s report timing with tie-breaking by SatelliteId.
Coding & AlgorithmsOnline Assessment - OptiverHardSoftware EngineerDesign a subscription push service
Design a subscription push service 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 - OptiverHardSoftware EngineerDesign a topic-based news subscription system
This question evaluates system design skills for building a topic-based news subscription service, focusing on streaming ingestion, relevance filtering, sliding-window rate limiting, de-duplication, ordered delivery, and data structure choices for in-memory operation.
System DesignOnline Assessment - OptiverMediumSoftware EngineerDesign an object-oriented queue and compare implementations
Design an object-oriented queue and compare implementations evaluates engineering fundamentals, trade-offs, examples, pitfalls, and operational implications in a realistic interview setting. A strong answer states assumptions, handles edge cases, explains trade-offs, and shows how to validate the result clearly.
Software Engineering FundamentalsTechnical Screen - OptiverHardSoftware EngineerDesign and backtest a trading strategy
This question evaluates a candidate's ability to design and rigorously evaluate a minute-level mean-reversion trading strategy, encompassing quantitative finance competencies such as signal construction, risk controls, position sizing, transaction-cost modeling, reproducible backtesting, and statistical validation; it belongs to the Analytics & Experimentation category within financial time-series and backtesting. It is commonly asked because it tests both practical implementation skills (reproducible backtests and walk-forward validation) and conceptual understanding (overfitting, data-snooping, and statistical significance testing), requiring a mix of practical application and conceptual statistical reasoning.
Analytics & ExperimentationTechnical Screen - OptiverMediumQuantitative ResearcherDesign dice betting strategy under time limit
This question evaluates probabilistic reasoning, expected-value computation, risk management and staking-strategy concepts including Kelly-style bet sizing, confidence-interval estimation, and return–variance trade-offs in the Statistics & Math domain.
Statistics & MathTechnical Screen - OptiverHardSoftware EngineerDesign low-latency trading infrastructure
Design an end-to-end low-latency market making and execution architecture split between an exchange-colocated environment and a remote operational office.
System DesignOnsiteLow LatencyHigh-Frequency TradingNetworking - OptiverHardSoftware EngineerDetect Currency Arbitrage After a Cycle Fee
You are given a matrix of positive currency exchange rates, where rates[i][j] units of currency j are received for one unit of currency i. Work through the function contract, boundary cases, correctness argument, and time and space complexity expected in a production-quality solution.
Coding & AlgorithmsTechnical Screen - OptiverMediumSoftware EngineerDetect currency arbitrage with costs
This question evaluates a candidate's competency in algorithmic problem modeling, graph-based cycle detection, and numerical reasoning about exchange rates and transaction costs.
Coding & AlgorithmsTechnical Screen - OptiverMediumQuantitative TraderDevise sequence-rule detection strategy
This question evaluates pattern-recognition, algorithm design, statistical reasoning, and model-selection skills required for sequence inference and candidate-term prediction in the Coding & Algorithms / Data Science domain.
Coding & AlgorithmsOnline Assessment - OptiverMediumSoftware EngineerEstimate expected comparisons in a BST
Estimate expected comparisons in a BST 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 & AlgorithmsOnline Assessment - OptiverMediumData ScientistExpected Wait for a Bus That Runs Late Half the Time
This question evaluates a candidate's understanding of probabilistic modeling and expectation calculations for stochastic arrival processes, touching on renewal-theory concepts and length-biased sampling phenomena relevant to timing and queuing problems.
Machine LearningTechnical Screen - OptiverMediumSoftware EngineerFastest 1000 Meters: Max Average Speed from 5-Second Distance Splits
Given the meters a runner covers in each consecutive 5-second interval, find the highest average speed over any continuous stretch of exactly 1000 meters, where stretches may start or end mid-interval. Tests sliding-window reasoning, linear interpolation at boundaries and edge cases such as one interval exceeding 1000 meters.
Coding & AlgorithmsOnline Assessment - OptiverMediumSoftware EngineerFastest 500-Unit Stretch on a Conveyor Belt From Tick Logs
Given how many units of material a conveyor belt moves during each fixed-length tick, find the maximum average speed over any continuous time stretch covering exactly 500 units, where the stretch may start or end mid-tick.
Coding & AlgorithmsOnline Assessmentsliding-windowtwo-pointersinterpolation - OptiverMediumSoftware EngineerFastest Rolling One-Kilometer Average Speed from 5-Second Distance Samples
Given the meters a runner covers in each 5-second interval, find the fastest average speed over a rolling one-kilometer stretch, defined as the shortest run of intervals ending at each point that covers at least 1000 meters. It tests sliding-window reasoning over large arrays and precise window definitions.
Coding & AlgorithmsOnline Assessment - OptiverEasyQuantitative ResearcherFermi Estimation with Confidence Intervals: How Many Houses Does One Year of US Netflix Spending Buy?
This question evaluates a candidate's quantitative estimation and uncertainty-quantification skills, focusing on decomposition into estimable factors, clear articulation of assumptions, calibrated confidence intervals, and updating estimates when new aggregate data are provided.
Machine LearningTechnical Screen - OptiverHardData ScientistFind missing numbers in sequences
This problem tests pattern recognition and algorithm design for identifying missing terms in a sequence that may follow arithmetic, geometric, polynomial, or linear recurrence rules.
Coding & AlgorithmsOnline AssessmentAlgorithmsPattern RecognitionNumerical Analysis - OptiverHardData ScientistFind next terms in sequences
This question evaluates pattern recognition, numerical reasoning, and sequence-inference competency across arithmetic, fractional, and recurrence-style relationships, and falls under the Statistics & Math domain relevant for data scientist roles.
Statistics & MathOnline Assessment - OptiverHardSoftware EngineerFind the Color Probability After Discarding Cards
This problem tests your understanding of conditional probability, combinatorics, and how dependent events (sampling without replacement) impact statistical expectations.
Statistics & MathTechnical ScreenProbabilityCombinatoricsStatistics - OptiverHardSoftware EngineerFind the Probability That the Three Smallest Dice Sum to Three
This problem tests combinatorics and probability theory by requiring the derivation of the exact probability that the three smallest values of four independent dice rolls sum to exactly three.
Statistics & MathTechnical ScreenProbabilityCombinatoricsStatistics - OptiverHardData ScientistHow to rank statements by likelihood
This problem tests your ability to translate statistical distributions and categorical data into ranked probabilistic likelihoods, accounting for uncertainty and sample size variance.
Machine LearningOnline AssessmentProbabilityStatisticsBayesian Inference - OptiverMediumSoftware EngineerIdentify OS component causing process starvation
This question evaluates understanding of process scheduling, kernel-level resource allocation, and starvation-related concurrency issues within the operating systems domain.
Coding & AlgorithmsOnline Assessment - OptiverHardSoftware EngineerImplement Expiration-Aware Retrieval Across Storage Levels
Design and implement a multi-level storage system that purges expired items, filters for under-utilized storage tiers, and deterministically retrieves the highest-weight item.
Software Engineering FundamentalsHR ScreenData StructuresDesignHeap - OptiverHardSoftware EngineerImplement a Multicore Overheat Prevention Controller
Simulate a multicore thermal controller with delayed workload changes, shared passive cooling, vibration-sensitive active cooling, shutdown and restart thresholds, and transition-only tick output.
Coding & AlgorithmsOnline Assessment - OptiverMediumSoftware EngineerImplement price-based order matcher
This question evaluates competency in data structures and algorithmic design for price-based order matching systems, including priority-based matching, efficient order book maintenance, and deterministic tie-breaking requirements.
Coding & AlgorithmsOnline Assessment
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