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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.
- 9403
- Questions
- 546
- Companies
- 11
- Topics
- 8
- Languages
Showing 7471–7500 of 9403 results
- RobloxMediumMachine Learning EngineerLevel-Ordered Dependency Build Order
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.
Coding & AlgorithmsTechnical ScreenGraphBFSTopological Sort - RobloxMediumData ScientistMatch requests and accepts into friendships in SQL
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.
Data Manipulation (SQL/Python)Onsite - RobloxMediumSoftware EngineerMatch-3 Grid: Find Horizontal and Vertical Runs, Then Clear and Drop Cells
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.
Coding & AlgorithmsTechnical Screen - RobloxMediumData ScientistMeasure Success for a New Chat System
Build a chat-system launch framework with meaningful communication metrics, reliability and safety guardrails, and experiments that address network effects.
Analytics & ExperimentationTechnical Screen - RobloxMediumSoftware EngineerNumber Line Obstacles: Check Whether a Centered Block Can Be Built
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.
Coding & AlgorithmsOnline Assessment - RobloxMediumData ScientistOptimize assembly-line scheduling with changeovers
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.
Coding & AlgorithmsOnline Assessment - RobloxMediumData ScientistOptimize bread-factory pipeline for max profit
This question evaluates skills in combinatorial optimization, budgeted resource allocation, bottleneck throughput modeling, and algorithm design with cost amortization for maximizing profit under constraints.
Coding & AlgorithmsOnsite - RobloxHardSoftware EngineerOutline the ML inference and labeling pipeline
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.
ML System DesignOnsite - RobloxMediumSoftware EngineerRandomly partition array into k segments
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.
Coding & AlgorithmsTechnical Screen - RobloxHardSoftware EngineerRank queries by prefix, frequency, and time
This question evaluates understanding of string processing, frequency aggregation, earliest-timestamp tracking, and efficient prefix-based retrieval for large datasets.
Coding & AlgorithmsTechnical Screen - RobloxMediumSoftware EngineerSelect Maximum Call Stacks Across Threads
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.
Software Engineering FundamentalsTechnical ScreenHash MapData StructuresDesign - RobloxMediumSoftware EngineerSimulate robot path and detect boundedness
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.
Coding & AlgorithmsOnsite - RobloxMediumSoftware EngineerTrail Campsite Clearance: Online Pin and Range-Empty Queries
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.
Coding & AlgorithmsOnline Assessmentfenwick-treecoordinate-compressionbinary-search - RobloxMediumData ScientistWrite SQL for ads metrics and variability
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.
Data Manipulation (SQL/Python)Technical Screen - RobloxEasyData ScientistWrite SQL for influence score and follower growth
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).
Data Manipulation (SQL/Python)Technical Screen - RobloxMediumData ScientistWrite SQL to flag suspect payments and chargebacks
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.
Data Manipulation (SQL/Python)HR Screen - RogoMediumMachine Learning EngineerInfer the Smallest Valid Character Order from Sorted Password Hints
This problem tests your ability to model dependency constraints using a Directed Acyclic Graph (DAG) and apply Kahn's algorithm or DFS-based topological sorting to resolve ordering dependencies.
Coding & AlgorithmsOnsiteGraphTopological SortPriority Queue - RogoMediumMachine Learning EngineerManage Context Windows in an Applied AI System
This question tests the ability to design a robust context-management layer for an LLM-based application that balances limited token capacity against competing sources of information.
ML System DesignOnsiteLLMRAGSystem Design - Rokos Capital ManagementMediumData ScientistExplain motivations and background for hedge fund role
This question evaluates a data scientist's background, motivation for working in a hedge fund, verbal communication and storytelling skills, and evidence of domain-relevant achievements from academics and internships.
Behavioral & LeadershipHR Screen - RoktEasySoftware EngineerImplement basic calculator with four operations
This question evaluates a candidate's ability to parse and evaluate arithmetic expressions, correctly apply operator precedence and left-to-right associativity, and handle integer arithmetic details such as truncating division, whitespace, and multi-digit numbers, and is commonly asked to assess implementation-level parsing and algorithmic reasoning. The category is Coding & Algorithms and the level of abstraction is practical application, focusing on coding an efficient evaluator that balances time and space constraints rather than purely conceptual theory.
Coding & AlgorithmsOnsite - RokuMediumSoftware EngineerCompute longest common subsequence length
This question tests the ability to solve the Longest Common Subsequence (LCS) problem using dynamic programming to optimize overlapping subproblems.
Coding & AlgorithmsOnsiteDynamic ProgrammingStringsAlgorithms - RokuMediumBackend EngineerDesign a high-throughput ad exchange
This problem tests your ability to design a low-latency, high-throughput distributed system capable of managing real-time bidding (RTB) auctions for streaming video advertisements.
System DesignOnsiteDistributed SystemsLow LatencyHigh Throughput - RokuMediumSoftware EngineerDesign a video-on-demand streaming service
This problem tests your ability to design a distributed video-on-demand platform, focusing on content ingestion, delivery at scale, and media processing pipelines.
System DesignOnsiteScalabilityCDNDistributed Systems - RokuEasyData ScientistExplain Bias-Variance Trade-off Simply for Stakeholders
Evaluates the ability to explain the bias-variance trade-off to non-technical stakeholders. Strong answers define bias as underfitting, variance as overfitting, use a clear analogy, and explain why models must generalize to new data rather than memorize training data.
Statistics & MathTechnical Screen - RokuMediumData ScientistExplain and quantify bias-variance tradeoff
This question tests the conceptual understanding of the bias-variance decomposition of mean squared error and how specific modeling choices influence these components.
Machine LearningTechnical ScreenBias-VarianceModel EvaluationSupervised Learning - RokuMediumBackend EngineerExplain concurrency and distributed fundamentals
This question tests fundamental knowledge of thread-safe collections in Java and core distributed systems architectural patterns, specifically partitioning strategies.
Software Engineering FundamentalsOnsiteJavaConcurrencyDistributed Systems - RokuMediumData ScientistMeasure Speaker's Impact Using Propensity Score Matching
Evaluates causal inference for optional smart speaker ownership using propensity score matching and staggered adoption. Strong answers address self-selection, construct matched or weighted controls, validate balance and pre-trends, estimate ATT, and run placebo and sensitivity analyses.
Analytics & ExperimentationTechnical Screen - RokuMediumData ScientistWrite SQL for profit, growth, retention
This question evaluates a candidate's ability to perform advanced SQL data manipulation — specifically rolling-window aggregations, revenue and gross profit computations that account for refunds, order status and test flags, plus cohort retention and week-over-week growth analysis.
Data Manipulation (SQL/Python)Technical Screen - RubrikMediumSoftware EngineerEngineering manager behavioral: driving a cross-team outcome from an ambiguous goal
An engineering manager behavioral prompt about owning an ill-defined goal that depended on other teams. It tests how a candidate removes ambiguity, secures cross-team commitments, runs execution through setbacks, and explains the specific decisions and trade-offs they personally made.
Behavioral & LeadershipOnsite - RubrikMediumSoftware EngineerEngineering manager interview: a leadership call you owned and an engineer you grew
A two-part engineering manager interview on leadership and mentorship. It asks for a situation where the candidate's own decision shaped the team's success and for a concrete account of growing an engineer, probing personal judgment, trade-offs and evidence of impact under targeted follow-ups.
Behavioral & LeadershipOnsite
Roblox
Rubrik