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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 4081–4110 of 9403 results
- Hudson River TradingMediumSoftware EngineerExplain and Diagnose a Segmentation Fault
This question tests your understanding of virtual memory, the lifecycle of a segmentation fault, and your ability to diagnose memory corruption using standard tooling.
Software Engineering FundamentalsTechnical ScreenC++SystemsDebugging - Hudson River TradingHardSoftware EngineerFinal Grid Position Under Timestamped Direction Changes With Dot Obstacles
An object on a grid changes direction whenever a timestamped action arrives and moves one cell per time unit until a blocked cell or the grid edge stops it. The task asks for its cell at a given end time, testing precise reading of the rules, including that dot cells are obstacles, and efficient handling of very large timestamps.
Coding & AlgorithmsTechnical Screen - Hudson River TradingHardSoftware EngineerFind a Local Minimum in One and Two Dimensions
Tests divide-and-conquer optimization techniques to locate a local minimum in 1D and 2D arrays in sublinear time, requiring rigorous reasoning about termination and invariants.
Software Engineering FundamentalsTechnical Screenbinary-searchdivide-and-conquerarrays - Hudson River TradingMediumSoftware EngineerFind the Longest Common Digit Prefix Across Two Arrays
Tests candidate's ability to efficiently match string/digit prefixes between two collections of integers using hash sets or a prefix tree (Trie).
Software Engineering FundamentalsTechnical ScreenTrieHash TableString - Hudson River TradingMediumSoftware EngineerFormat an Integer with Thousands Separators
Implement a function that formats a signed integer with a custom thousands separator character without relying on built-in string formatting utilities.
Coding & AlgorithmsTechnical Screenstringmathimplementation - Hudson River TradingMediumQuantitative ResearcherImplement Buffer Parsers and Generic Map Class
This problem tests your ability to safely parse binary data streams from raw memory buffers and implement a type-safe generic wrapper around standard associative containers.
Coding & AlgorithmsOnline AssessmentC++TemplatesBinary-Parsing - Hudson River TradingHardSoftware EngineerImplement Order Modification Feature
This question evaluates a software engineering competency in modifying and extending a C++ client/server trading system, focusing on state management, input validation, API integration, and maintaining invariants for order lifecycle.
Coding & AlgorithmsOnsite - Hudson River TradingMediumSoftware EngineerLinux Host and Filesystem Fundamentals
Review practical Linux fundamentals: memory and swap interpretation, safe directory enumeration, process-versus-thread trade-offs, filesystem links, and option-safe file deletion. Also explain responsible recovery steps after an accidental recursive delete.
Software Engineering FundamentalsTechnical Screen - Hudson River TradingEasySoftware EngineerMaximize Item Counts Under Suffix Budget Queries
Determine the maximum number of items that can be purchased from a suffix of an item array within a given budget for multiple independent queries.
Coding & AlgorithmsHR Screengreedysortingbinary-search - 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 EngineerBreak Adjacent Duplicate Characters
Tests string traversal, run-length counting, and greedy optimization to determine the minimum character replacements needed to eliminate adjacent identical characters across a list of words.
Coding & AlgorithmsOnline AssessmentStringsGreedyAlgorithms - IBMEasySoftware EngineerCalculate Revenue from Highest-Inventory VM Sales
Sell each VM unit at its current inventory count, always choose a type with maximum inventory, and compute total revenue safely.
Coding & AlgorithmsOnline Assessment - 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
Hudson River Trading
IBM