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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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- 546
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- 11
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Showing 1981–2010 of 4616 results
- Hudson River TradingMediumSoftware EngineerMinimize Array Amplitude After Removing a Contiguous Block
Tests array manipulation and prefix/suffix extremum tracking to minimize the spread (max - min) of an array after removing a contiguous subarray of length k.
Software Engineering FundamentalsTechnical Screenarraysprefix-suffixsliding-window - Hudson River TradingMediumSoftware EngineerPython Language and Runtime Fundamentals
Review core Python semantics through decorators, dictionary hashing, generators, unpacking syntax, and memory management. Distinguish language guarantees from CPython behavior while connecting edge cases to API design, debugging, and safe resource cleanup.
Software Engineering FundamentalsTechnical Screen - Hudson River TradingMediumSoftware EngineerQuery Order and Batch Lifetimes from Event Files
Design an event-driven tracker to query lifetimes for individual orders or order batches, correctly handling open orders and aggregate start/end timestamps.
Software Engineering FundamentalsTechnical Screenhash-tablesystem-fundamentalsdata-structures - Hudson River TradingHardSoftware EngineerReason About C++ Inlining, Allocation, and Polymorphism
Tests deep C++ systems knowledge regarding the runtime and compiler-level impacts of dynamic dispatch, heap allocations, and function inlining within latency-sensitive pipelines.
Software Engineering FundamentalsTechnical Screencppsystems-programmingmemory-management - Hudson River TradingMediumSite Reliability EngineerReason About Unix Signals, Zombies, and Process Reaping
Assess understanding of Unix process lifecycles, signal handling mechanics, zombie state accumulation, and process reaping responsibilities in parent processes and PID 1.
Software Engineering FundamentalsTechnical Screenunixlinux-kernelsystems - Hudson River TradingMediumSoftware EngineerReturn the K Smallest Integers
Implement an algorithm to extract the k smallest integers from an unsorted list in ascending order, preserving duplicates, and analyze the trade-offs between sorting, heaps, quickselect, and bounded-range approaches.
Coding & AlgorithmsTechnical ScreenHeapQuickselectSorting - Hudson River TradingMediumSoftware EngineerSimulate Alternating Stick Collection for a Nest
Tests simulation logic, two-pointer state management, turn alternation, and handling conditional decision rules with edge cases.
Coding & AlgorithmsTechnical ScreenTwo PointersSimulationGreedy - Hudson River TradingMediumSoftware EngineerSimulate Players Moving Under a Watcher's Gaze
Simulate the movement and freezing of players on a 1D track under the gaze of a moving watcher who reverses direction at specified times.
Coding & AlgorithmsTechnical Screensimulationarraystwo-pointers - Hudson River TradingEasySoftware EngineerSmallest Integer Point Lit by the Most Street Lamps on a Line
Online assessment coding problem: street lamps on a number line each light a closed interval around their position, and you must return the integer point lit by the most lamps, choosing the smallest such point on ties. It tests interval overlap counting over very large coordinate ranges.
Coding & AlgorithmsTechnical Screen - Hudson River TradingMediumData ScientistSolve Dice Probability and Matrix Questions
This problem tests probability distributions over modular arithmetic and the identification of properties of doubly stochastic matrices.
Machine LearningTechnical ScreenProbabilityLinear AlgebraMatrices - Hudson River TradingMediumSoftware EngineerSolve Watcher Simulation And Integer Conversion
This question evaluates event-driven simulation and discrete-time state modeling for tracking multiple agents under dynamic visibility constraints, together with low-level numeric string conversion and edge-case handling for 32-bit signed integers.
Coding & AlgorithmsTechnical Screen - Hudson River TradingMediumSoftware EngineerSplit a Message into Length-Limited Parts with Numbered Suffixes
This problem tests your ability to handle string manipulation, edge-case arithmetic, and iterative construction while adhering to dynamic length constraints imposed by mandatory metadata.
Software Engineering FundamentalsTechnical ScreenStringsGreedySimulation - Hudson River TradingMediumSoftware EngineerTest easy–medium array/string tasks
This question evaluates a candidate's ability to design concise, robust test cases and translate edge-case reasoning into concrete inputs and expected outputs for array and string problems, reflecting skills in input validation, correctness assurance, and handling varied data characteristics.
Coding & AlgorithmsTechnical Screen - Hudson River TradingMediumSite Reliability EngineerTroubleshoot a Host That Rejects SSH Connections
Tests systematic Linux systems and networking troubleshooting methodology by designing an evidence-based diagnostic path for an unreachable or rejecting SSH service.
Software Engineering FundamentalsTechnical Screenlinuxnetworkingtroubleshooting - Hudson River TradingHardSoftware EngineerWhy pursue full-stack engineering?
This question evaluates motivation, problem-selection preferences, cross-functional collaboration, and full-stack thinking as competencies relevant to a Software Engineer, and it falls under the Behavioral & Leadership category.
Behavioral & LeadershipTechnical Screen - Hudson River TradingHardSoftware EngineerWrap a Fixed-Chunk Stream Reader with Arbitrary-Length Reads
Implement an arbitrary-length stream reader on top of an underlying reader that only yields data in fixed-size chunks, managing internal buffering and end-of-stream state across successive calls.
Software Engineering FundamentalsTechnical ScreenStreamsBufferingSystems Programming - HuluMediumData ScientistDesign and Monitor a Multi-Country Parameter Experiment
This question tests the ability to design an A/B test across multiple regions while accounting for sample size requirements, variance reduction techniques, and sequential monitoring protocols.
Analytics & ExperimentationTechnical ScreenA/B TestingPower AnalysisCUPED - HuluMediumData ScientistInterpret a Streaming Regression Without Overstating Causality
This problem tests your ability to interpret multivariate regression results for product stakeholders, specifically focusing on distinguishing correlation from causation and identifying risks like collider bias.
Analytics & ExperimentationTechnical ScreenRegressionCausal InferenceExperimental Design - IBMMediumSoftware EngineerCount Employees With Unbroken Renewable Access at the Last Timestamp
A simulation problem about an access system where each employee's access lasts a fixed duration after every setting and can be extended only while it is still active. It asks how many employees hold valid access at the last timestamp, testing exact expiry boundaries, permanent lapses and per-employee state.
Coding & AlgorithmsTechnical Screen - IBMMediumSoftware EngineerCount Index Triplets Whose Max Minus Min Is at Most d
A counting problem that asks how many triplets of positions in an integer array have a spread, the largest value minus the smallest, of at most d. It tests handling duplicates and inclusive bounds, producing a count that can exceed 32 bits, and meeting time limits for arrays of up to 100,000 elements.
Coding & AlgorithmsTechnical Screen - IBMMediumSoftware EngineerCount Seat-Price Trios Within a Budget Spread
Count how many trios of resale-marketplace seat listings have prices within a fixed budget spread of each other, using sorting and a two-pointer sweep instead of an O(n^3) scan.
Coding & AlgorithmsTechnical Screensortingtwo-pointerscombinatorics - IBMMediumSoftware EngineerCount Sensor Trios Within a Tolerance Band
Count how many groups of three readings stay inside a tolerance band (max minus min within a limit). Tests sorting, a sliding window, combinatorial counting and handling of duplicates and large totals.
Coding & AlgorithmsTechnical Screensortingtwo-pointerscombinatorics - IBMEasyData ScientistDesign a lead-scoring model
Design an end-to-end lead-scoring model for a marketing/growth data science team: define the label and scoring time, engineer leakage-safe features, compare a logistic-regression baseline with gradient-boosted trees, and evaluate with capacity-aware ranking metrics. The question also probes multicollinearity, model interpretability (SHAP/reason codes), routing-threshold design, and operational risks like selection bias, class imbalance, fairness, and drift.
Machine LearningTechnical Screen - IBMEasyData ScientistEstimate free-trial conversion probability
This question evaluates a data scientist's competency in cohort definition, censored-data handling, segmentation and confounding assessment, and uncertainty quantification for measuring free-trial to paid conversion, and it belongs to the Analytics & Experimentation domain within data science.
Analytics & ExperimentationTechnical Screen - IBMMediumSoftware EngineerFind minimum subarray length with k distinct integers
This question tests proficiency with the sliding window technique and hash map-based frequency tracking, applied to subarray problems requiring exact cardinality constraints. It assesses the ability to distinguish between "exactly k distinct" and "at most k distinct" variants — a nuance that reveals depth in algorithmic thinking commonly evaluated in software engineering interviews.
Coding & AlgorithmsTechnical Screen - IBMMediumSoftware EngineerFunction Signature Lookup with Exact and Variadic Parameter Matching
A coding question about an IDE-style signature lookup engine: given registered functions, some whose last parameter is variadic, return for each call the sorted names of every function that accepts its argument types. It tests exact type-sequence matching, zero-or-more variadic arguments and edge cases such as empty argument lists.
Coding & AlgorithmsTechnical Screen - IBMEasyData ScientistHow do you detect and fix multicollinearity?
This question evaluates understanding of multicollinearity and related competencies in regression diagnostics, feature engineering, model interpretability, and the trade-offs between coefficient inference and predictive performance.
Statistics & MathTechnical Screen - IBMMediumSoftware EngineerMaximize palindromic strings after character swaps
This question evaluates proficiency in string manipulation, combinatorial character-count reasoning, and redistribution of characters under constrained swap operations within the Coding & Algorithms domain.
Coding & AlgorithmsTechnical Screen - IXL LearningEasySoftware EngineerDebug Kubernetes crashes and review Python ingestion script
This question evaluates operational debugging and system reliability skills — specifically Kubernetes pod/container troubleshooting, health-probe configuration, and practical Python ETL code review, focusing on observability, dependency management, and production-readiness.
Software Engineering FundamentalsTechnical Screen - IXL LearningMediumSoftware EngineerFind value on most distinct levels
This question evaluates a candidate's understanding of binary tree structures, level-wise aggregation and frequency analysis, along with algorithm design and complexity reasoning.
Coding & AlgorithmsTechnical Screen
Hudson River Trading
IBM
IXL Learning