Roblox interview questions

Showing 61–84 of 84 results

• Implement a Log Rate LimiterMedium

  This problem tests your ability to design a thread-safe, time-windowed rate limiter using efficient data structures to track event timestamps.

  RobloxSoftware EngineerCoding & AlgorithmsOnsite
• Implement a Rolling-Window Rate LimiterMedium

  Implement an in-memory, rolling-window rate limiter supporting per-client limits, precise boundary expiration, and stale state cleanup.

  RobloxSoftware EngineerSoftware Engineering FundamentalsTechnical Screen
• Implement a sliding-window rate limiterMedium

  Evaluates the candidate's ability to design and implement an in-memory sliding-window rate limiter enforcing per-user and per-game constraints, focusing on correct request-acceptance semantics and efficient timestamp eviction; Category/domain: Coding & Algorithms; Level of abstraction: component-level algorithm and data-structure implementation.

  RobloxSoftware EngineerCoding & AlgorithmsOnsite
• Implement four DS coding tasksEasy

  This multi-part question evaluates a data scientist's competencies in statistical inference (sample size and z-test calculations), causal inference and parallel-trends validation (difference-in-differences), Bayesian probability updating, and interpretable supervised learning feature importance, all framed as coding tasks.

  RobloxData ScientistCoding & AlgorithmsOnline Assessment
• Implement queue-based rate limiter with multi-key limitsMedium

  This question evaluates implementation and design skills around rate limiting, including rolling-window counters, multi-key constraints, and atomic updates, and falls under the Coding & Algorithms domain focused on practical application of algorithms and data structures.

  RobloxSoftware EngineerCoding & AlgorithmsOnsite
• Implement recent-requests counterEasy

  This question evaluates a candidate's ability to design efficient in-memory data structures and manage time-windowed event counting, testing algorithmic reasoning and performance optimization for high-throughput services.

  RobloxMachine Learning EngineerCoding & AlgorithmsTechnical Screen
• Implement robust one/two-sided p-value functionHard

  This question evaluates proficiency in statistical hypothesis testing, numerical computing, and numerical stability when implementing p-value calculations for z and t distributions, and it targets the Statistics & Math domain for a data scientist role.

  RobloxData ScientistStatistics & MathTechnical Screen
• Implement streaming CTR with deduplicationMedium

  This question evaluates streaming data-processing and algorithmic design skills, specifically time-windowed aggregation, click deduplication, late-event handling, state management, and selection of data structures for per-campaign CTR computation.

  RobloxData ScientistCoding & AlgorithmsTechnical Screen
• Level-Ordered Dependency Build OrderMedium

  This problem tests your ability to perform a Kahn’s algorithm-based topological sort while grouping tasks into parallelizable layers, ensuring cycle detection and dependency validation.

  RobloxMachine Learning EngineerCoding & AlgorithmsTechnical Screen
• Match requests and accepts into friendships in SQLMedium

  This question evaluates a candidate's competency in SQL data manipulation, focusing on temporal joins, deduplication of bidirectional relationships, selecting the earliest valid event, and reasoning about event-order constraints.

  RobloxData ScientistData Manipulation (SQL/Python)Onsite
• Match-3 Grid: Find Horizontal and Vertical Runs, Then Clear and Drop CellsMedium

  A two-part grid problem modeled on a Match-3 game: report every horizontal and vertical run of three or more equal values in a fixed scan order, then clear the matched cells and let the remaining values in each column fall to the bottom. It tests precise run detection, ordering rules and grid simulation.

  RobloxSoftware EngineerCoding & AlgorithmsTechnical Screen
• Measure Success for a New Chat SystemMedium

  Build a chat-system launch framework with meaningful communication metrics, reliability and safety guardrails, and experiments that address network effects.

  RobloxData ScientistAnalytics & ExperimentationTechnical Screen
• Number Line Obstacles: Check Whether a Centered Block Can Be BuiltMedium

  Process operations on an infinite integer number line that either place an obstacle or ask whether a block centered at a point, reaching a given distance in each direction, is free of obstacles, and return the answers as a binary string. It tests efficient online range queries over large, sparse coordinates.

  RobloxSoftware EngineerCoding & AlgorithmsOnline Assessment
• Optimize assembly-line scheduling with changeoversMedium

  This question evaluates combinatorial optimization and scheduling competencies, specifically reasoning about NP-hardness, sequence-dependent setup times, precedence and downtime constraints, and designing exact and heuristic solvers for makespan minimization.

  RobloxData ScientistCoding & AlgorithmsOnline Assessment
• Optimize bread-factory pipeline for max profitMedium

  This question evaluates skills in combinatorial optimization, budgeted resource allocation, bottleneck throughput modeling, and algorithm design with cost amortization for maximizing profit under constraints.

  RobloxData ScientistCoding & AlgorithmsOnsite
• Outline the ML inference and labeling pipelineHard

  Outline the ML inference and labeling pipeline evaluates ML product requirements, data/labeling, modeling, serving architecture, evaluation, monitoring, and trade-offs in a realistic interview setting. A strong answer states assumptions, handles edge cases, explains trade-offs, and shows how to validate the result clearly.

  RobloxSoftware EngineerML System DesignOnsite
• Randomly partition array into k segmentsMedium

  This question evaluates algorithm design, randomization techniques, and time/space complexity analysis within the Coding & Algorithms domain, focusing on partitioning an array into random non-empty segments.

  RobloxSoftware EngineerCoding & AlgorithmsTechnical Screen
• Rank queries by prefix, frequency, and timeHard

  This question evaluates understanding of string processing, frequency aggregation, earliest-timestamp tracking, and efficient prefix-based retrieval for large datasets.

  RobloxSoftware EngineerCoding & AlgorithmsTechnical Screen
• Select Maximum Call Stacks Across ThreadsMedium

  Design an in-memory profiler aggregator to track sampled call stacks across threads, returning the most frequent stacks globally and per-thread with deterministic tie-breaking.

  RobloxSoftware EngineerSoftware Engineering FundamentalsTechnical Screen
• Simulate robot path and detect boundednessMedium

  This question evaluates the ability to simulate iterative movement and reason about repeated state transformations, testing competencies in algorithm design, cycle detection, and geometric reasoning; it falls under the Coding & Algorithms category.

  RobloxSoftware EngineerCoding & AlgorithmsOnsite
• Trail Campsite Clearance: Online Pin and Range-Empty QueriesMedium

  Process a stream of events that drop hazard pins at integer mile markers or ask whether a campsite centered at a marker with a given radius would be hazard-free, returning the answers as a string. Tests sparse-coordinate range counting with binary search and a Fenwick tree.

  RobloxSoftware EngineerCoding & AlgorithmsOnline Assessment
• Write SQL for ads metrics and variabilityMedium

  This question evaluates a candidate's ability to perform SQL-based data manipulation and analytics, including deduplication of events, computation of daily and campaign-level metrics (CTR, CPC), and calculation of statistical summaries (mean and standard deviation) and outlier detection over a specified date range.

  RobloxData ScientistData Manipulation (SQL/Python)Technical Screen
• Write SQL for influence score and follower growthEasy

  This question evaluates SQL data manipulation competencies such as joins, aggregations, distinct counts, window functions, and time-based grouping for computing an influence score (engagements on a user's posts plus follower count) and monthly follower growth, and it falls under Data Manipulation (SQL/Python).

  RobloxData ScientistData Manipulation (SQL/Python)Technical Screen
• Write SQL to flag suspect payments and chargebacksMedium

  This question evaluates proficiency with SQL conditional logic (CASE WHEN), JOINs, date/time arithmetic, aggregation, and encoding business rules for flagging suspect payments and chargebacks, and is categorized under Data Manipulation (SQL/Python) for a Data Scientist role.

  RobloxData ScientistData Manipulation (SQL/Python)HR Screen