Hudson River Trading interview questions

Showing 1–30 of 55 results

• Approach verbose data-structure designMedium

  This question evaluates a candidate's ability to design and implement complex data structures, testing algorithmic reasoning, time/space complexity analysis, state modeling, and organization of code and tests.

  Hudson River TradingSoftware EngineerCoding & AlgorithmsTechnical Screen
• Ball Position in a Tilting Maze After Timed Tilt EventsEasy

  Live coding simulation problem: a ball sits in a grid maze on a board that can tilt up, down, left or right or lie flat, and timed events change the tilt. Return the ball's cell at an end time that can be very large. It tests precise timing rules, wall handling and movement code that scales to long time spans.

  Hudson River TradingSoftware EngineerCoding & AlgorithmsTechnical Screen
• Build a Heart Disease BaselineHard

  This question evaluates proficiency in applied machine learning workflows, including data inspection and cleaning, exploratory data analysis, feature engineering, baseline binary classification modeling, and evaluation using Python libraries like pandas and seaborn.

  Hudson River TradingSoftware EngineerMachine LearningOnsite
• C++ Fundamentals: Memory, Compilation, and ContainersHard

  Tests deep C++ expertise in zero-allocation data structures, cache-line alignment, manual object lifecycle management via placement new, and the compilation/inlining implications of template-based designs.

  Hudson River TradingSoftware EngineerSoftware Engineering FundamentalsTechnical Screen
• Calculate Completion Time for a Single-Server Reactor QueueMedium

  Simulate a single-threaded reactor queue with a bounded buffer to compute the completion timestamp or drop status for each incoming task.

  Hudson River TradingSoftware EngineerCoding & AlgorithmsTechnical Screen
• Check Root-To-Leaf Target Sums In A Binary TreeEasy

  This question tests your ability to traverse a binary tree using depth-first search (DFS) or breadth-first search (BFS) while tracking path accumulators and accurately identifying valid leaf nodes.

  Hudson River TradingSoftware EngineerCoding & AlgorithmsTechnical Screen
• Choose Mean or Median for Trading Profit MetricsMedium

  This problem tests your understanding of statistical measures of central tendency, specifically how different distributions affect the choice between mean and median in high-frequency trading scenarios.

  Hudson River TradingSoftware EngineerStatistics & MathTechnical Screen
• Compare C++ Pointers and ReferencesMedium

  Tests in-depth understanding of C++ raw pointers versus references, their language semantics, memory representations, and how to apply them to design safe, idiomatic, zero-cost APIs.

  Hudson River TradingSoftware EngineerSoftware Engineering FundamentalsTechnical Screen
• Compare C++ Virtual Dispatch with CRTPMedium

  Compare C++ virtual dispatch with CRTP across runtime flexibility, object layout, separate compilation, heterogeneous collections, inlining, code size, diagnostics, ABI stability, and measured performance.

  Hudson River TradingSoftware EngineerSoftware Engineering FundamentalsOnsite
• Compare Mean and Median for a Distribution with a Point MassMedium

  This question tests the theoretical and empirical comparison between the sample mean and sample median on a mixture distribution containing a discrete point mass and a Gaussian component.

  Hudson River TradingData ScientistStatistics & MathTechnical Screen
• Compare Multithreading and MultiprocessingMedium

  This question tests your understanding of concurrency primitives, operating system process models, memory isolation, context switching overheads, and the architectural trade-offs between threads and processes in low-latency systems.

  Hudson River TradingSoftware EngineerSoftware Engineering FundamentalsTechnical Screen
• Compare Python Generators, Decorators, and Context ManagersMedium

  Tests understanding of Python's execution timing, protocol methods, and resource cleanup across generators, decorators, and context managers, culminating in a robust lazy stream processor.

  Hudson River TradingSite Reliability EngineerSoftware Engineering FundamentalsTechnical Screen
• Count Digit-Reversal Equivalent PairsMedium

  Count pairs of indices in an integer array whose values share the same canonical digit-reversal form.

  Hudson River TradingSoftware EngineerCoding & AlgorithmsTechnical Screen
• Count Length-3 Chat Substrings with a VowelMedium

  Count the number of distinct length-3 alphabetical substrings in a chat message that contain at least one vowel.

  Hudson River TradingSoftware EngineerCoding & AlgorithmsTechnical Screen
• Count Matrix Cells Whose Row and Column Neighbors MatchMedium

  This problem tests your ability to efficiently traverse a grid while implementing conditional neighborhood logic and handling boundary constraints.

  Hudson River TradingSoftware EngineerSoftware Engineering FundamentalsTechnical Screen
• Count People Reaching the BoundaryEasy

  This question evaluates algorithmic simulation and event-driven modeling skills, specifically handling discrete versus continuous time, visibility constraints relative to a stationary watcher that changes facing direction, and boundary conditions for state transitions.

  Hudson River TradingMachine Learning EngineerCoding & AlgorithmsOnsite
• Count Smaller Numbers with Only Zero and One in Base FourMedium

  Count the number of positive integers strictly less than n whose base-4 representation consists only of the digits 0 and 1.

  Hudson River TradingData ScientistCoding & AlgorithmsOnline Assessment
• Count inversions in a permutationMedium

  This question evaluates understanding of inversion counting in permutations, testing algorithmic problem-solving, complexity analysis, and data-structure reasoning about pairwise order relations.

  Hudson River TradingData ScientistCoding & AlgorithmsTechnical Screen
• Count players reaching end with moving watchersEasy

  This problem tests your ability to model state transitions over discrete time steps and efficiently track interval coverage using sorting and sweep-line logic.

  Hudson River TradingSoftware EngineerCoding & AlgorithmsTechnical Screen
• Derive expected inversions and mean distributionMedium

  This problem tests your understanding of linearity of expectation and variance properties applied to permutation statistics, as well as the ability to design a simulation to verify analytical derivations.

  Hudson River TradingData ScientistMachine LearningTechnical Screen
• Design a Fixed-Size Memory Allocator with Correct AlignmentMedium

  Design a slab-backed fixed-size allocator with constant-time free-list operations, correct stride and alignment, separate object lifetime, corruption defenses, concurrency choices, and efficient handling of nine-byte payloads.

  Hudson River TradingSoftware EngineerSoftware Engineering FundamentalsOnsite
• Design an Indexable Deque with O(1) AccessHard

  Tests understanding of low-level data structure design, memory layout, and trade-offs required to build a double-ended queue supporting strict O(1) random indexing and amortized O(1) push/pop operations.

  Hudson River TradingSoftware EngineerSoftware Engineering FundamentalsTechnical Screen
• Design comprehensive OA test casesMedium

  This question assesses a software engineer's practical test design skills under time pressure, specifically the ability to partition input spaces into equivalence classes and boundary cases for algorithm and data structure problems. It evaluates systematic testing methodology, including oracle-based verification strategies and defensible stopping rules — competencies commonly probed in online assessments and technical interviews to gauge engineering rigor.

  Hudson River TradingSoftware EngineerBehavioral & LeadershipTechnical Screen
• Determine Whether Two Integers Sum to a TargetMedium

  This problem tests proficiency with hash sets to achieve linear time complexity and emphasizes defensive programming practices like input validation and immutability.

  Hudson River TradingSoftware EngineerCoding & AlgorithmsTechnical Screen
• Diagnose I/O, Memory, and CPU ConstraintsMedium

  Tests your ability to systematically diagnose, measure, and resolve CPU, memory, and I/O bottlenecks in high-throughput, low-latency systems.

  Hudson River TradingSoftware EngineerSoftware Engineering FundamentalsTechnical Screen
• Explain C++ Inline, Segfaults, Virtual Memory, and std::string InternalsHard

  Tests deep understanding of low-level systems and modern C++ fundamentals, focusing on compiler inlining mechanics, virtual memory paging, segmentation fault root causes, and standard library string memory layouts.

  Hudson River TradingSoftware EngineerSoftware Engineering FundamentalsTechnical Screen
• Explain Large Memory Allocation, Swap, and C++ Inline Trade-offsHard

  Tests deep understanding of OS virtual memory management, demand paging and swap mechanics, and low-latency C++ compiler optimizations centered around inlining and instruction cache trade-offs.

  Hudson River TradingSoftware EngineerSoftware Engineering FundamentalsTechnical Screen
• Explain Python and React performance fundamentalsHard

  This question evaluates knowledge of Python resource management (context managers and the with statement), React rendering and optimization concepts (hooks, memoization, and frontend performance), and on-call debugging and incident triage skills.

  Hudson River TradingSoftware EngineerSoftware Engineering FundamentalsTechnical Screen
• Explain Virtual Memory, MMUs, and TLBsMedium

  Trace a virtual-memory load through TLB lookup, page-table walking, MMU permission checks, cache and physical access, page-fault handling, context switches, huge pages, and cross-core shootdowns.

  Hudson River TradingSoftware EngineerSoftware Engineering FundamentalsOnsite
• Explain Why du and df Report Different Disk UsageMedium

  This question tests your understanding of Linux filesystem internals, specifically how kernel-level storage reporting differs from user-space directory traversal.

  Hudson River TradingSite Reliability EngineerSoftware Engineering FundamentalsTechnical Screen