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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
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- 11
- Topics
- 8
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Showing 601–630 of 781 results
- RobloxHardData ScientistCompute sample size and Bayes posterior
This question evaluates understanding of statistical inference and probabilistic reasoning by combining a frequentist power/sample-size computation for a two-sided two-sample z-test with a basic Bayesian conditional probability calculation.
Statistics & MathOnline Assessment - RobloxMediumSoftware EngineerData Center Rack Units: Can a Centered Equipment Bay Be Reserved?
Process an online stream of rack-unit reservations and span-availability checks over an infinite 1D coordinate line, answering each availability check with the data seen so far.
Coding & AlgorithmsOnline Assessmentbinary-searchonline-queriesarrays - RobloxHardData ScientistDesign leakage-free predictive maintenance pipeline
This question evaluates a data scientist's competency in designing time-series predictive maintenance pipelines, focusing on temporal feature engineering, leakage prevention and point-in-time joins, handling late-arriving labels, class imbalance and cost-sensitive thresholding, probabilistic calibration, explainability, and operational drift monitoring. It is commonly asked in the Machine Learning domain to assess an applicant's ability to produce an end-to-end, production-ready workflow that balances practical implementation concerns with conceptual system-design reasoning, so the task is primarily practical application with important conceptual elements.
Machine LearningOnline Assessment - RobloxMediumSoftware EngineerFind the Longest Safe Straight-Line Movement on a Laser Grid
Find a robot's longest safe straight-line movement on a laser-covered grid, where only the initial cell is protected and laser rows and columns are blocked.
Coding & AlgorithmsOnline Assessment - RobloxHardData ScientistFit logistic regression and return top features
This question evaluates understanding of binary logistic regression, coefficient-based feature importance, and practical model-fitting considerations such as intercept inclusion and input shape handling.
Machine LearningOnline Assessment - RobloxMediumSoftware EngineerHandle Release Risks and Cross-Team Blockers
Assess a candidate's ability to navigate high-stakes release deadlines when facing upstream dependencies, critical bugs, and cross-team roadblocks.
Behavioral & LeadershipOnline AssessmentBehavioralRelease ManagementCross-Team Collaboration - RobloxEasyData ScientistImplement four DS coding tasks
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.
Coding & AlgorithmsOnline Assessment - 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 - 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 - RubrikHardSoftware EngineerFind largest connected group of overlapping intervals
This question evaluates understanding of interval overlap modeling, graph connectivity, and algorithmic efficiency by requiring mapping time intervals to an undirected communication graph and identifying its largest connected component.
Coding & AlgorithmsOnline Assessment - RubrikHardSoftware EngineerValidate BFS order queries on a tree
This question evaluates understanding of BFS traversal, tree graph representation, and the ability to reason about allowable dequeue/enqueue orderings in a FIFO queue.
Coding & AlgorithmsOnline Assessment - SIG (Susquehanna)MediumQuantitative TraderBayesian Posterior That k Red Parts Came From Factory A
A probability question on Bayesian updating: one of two factories with different red-part rates is chosen at random, and k parts drawn from it are all red. It asks for the conditional probability that the parts came from the first factory, testing likelihoods, priors and careful evaluation of powers.
Statistics & MathOnline Assessment - SIG (Susquehanna)EasyData ScientistCalculate Expected Payoff from Two Dice
This problem tests fundamental knowledge of probability, expected value, and partitioning sample spaces to calculate the average outcome of a stochastic process.
Statistics & MathOnline AssessmentProbabilityExpected ValueStatistics - SIG (Susquehanna)EasyData ScientistCompute Conditional Age Probability Among Cyclists
This question tests the ability to interpret a contingency table and calculate conditional probabilities by narrowing the sample space to a specific sub-group.
Statistics & MathOnline AssessmentProbabilityStatisticsContingency Tables - SIG (Susquehanna)MediumData ScientistCompute ruin probability with bold betting
This question evaluates understanding of probability theory and stochastic processes, focusing on ruin probabilities under a bold betting strategy with state-dependent wagers.
Statistics & MathOnline Assessment - SIG (Susquehanna)EasyData ScientistCompute stockout sufficiency probability
This question evaluates understanding of discrete probability and binomial models for independent Bernoulli trials, testing the ability to compute the probability that a limited resource meets random demand.
Statistics & MathOnline Assessment - SIG (Susquehanna)EasyData ScientistCompute the Probability Two Bloom Intervals Overlap
Calculate the probability that two independent events with different known durations overlap within a fixed time window using geometric probability.
Statistics & MathOnline AssessmentProbabilityContinuous DistributionsGeometric Probability - SIG (Susquehanna)EasyData ScientistCondition on a Chosen Rabbit Losing
Calculate the conditional probability that a randomly selected rabbit is the least athletic of three rabbits given that it lost its benchmark race, using Bayes' theorem.
Statistics & MathOnline AssessmentProbabilityBayes' TheoremConditional Probability - SIG (Susquehanna)EasyData ScientistCount Cookie Flavor Combinations
Calculate the number of distinct unordered combinations when selecting 5 cookies from 4 available flavors with replacement, and contrast this with the ordered outcome space.
Statistics & MathOnline Assessmentcombinatoricsstars-and-barsprobability - SIG (Susquehanna)MediumSoftware EngineerCount Equal-Difference Triples After Each Add or Remove-All Operation
Process a stream of add-one and remove-all operations on a multiset and report, after each operation, how many element triples form an arithmetic progression with a fixed positive difference. It tests efficient incremental updates, correct treatment of duplicate occurrences, and counts that exceed the 32-bit range.
Coding & AlgorithmsOnline Assessment - SIG (Susquehanna)EasyData ScientistCount Grid Paths with No Three Equal Moves
Count lattice paths from `(0, 0)` to `(5, 5)` that never use three identical directions consecutively. The solution converts paths into alternating runs of length one or two, counts bounded compositions for equal and unequal run totals, and derives 84 valid paths.
Statistics & MathOnline Assessment - SIG (Susquehanna)MediumSoftware EngineerCount subarrays with odd zero count
This interview question evaluates algorithm design, data structures, correctness, complexity, edge cases, and implementation details in a realistic interview setting. A strong answer for Count subarrays with odd zero count states assumptions, handles edge cases, explains trade-offs, and shows how to validate the result clearly.
Coding & AlgorithmsOnline Assessment - SIG (Susquehanna)EasyData ScientistDeduce Cat Counts from Conditional Truth Rules
Deduce the exact number of cats owned by three individuals based on conditional truth-telling rules, percentage relations, and average constraints.
Statistics & MathOnline AssessmentLogic PuzzleNumber TheoryIntegrality - SIG (Susquehanna)EasyData ScientistDetermine a Canoe Departure Time
This problem tests algebraic modeling and systems of linear equations by requiring the candidate to derive the counts of different entities based on a total sum constraint.
Statistics & MathOnline AssessmentAlgebraLinear EquationsLogic - SIG (Susquehanna)MediumData ScientistDetermine departure time from travel times
This question evaluates a candidate's understanding of relative motion, time-distance-rate relationships, algebraic modeling, and quantitative reasoning. Commonly asked in technical interviews for Statistics & Math and Data Scientist roles, it assesses the practical application of setting up and manipulating equations from multi-step word problems rather than purely conceptual theory.
Statistics & MathOnline Assessment - SIG (Susquehanna)MediumQuantitative TraderExpected Number of Same-Rank Pairs in a Hand Dealt Without Replacement
An expectation question about dealing K cards without replacement from a deck of M ranks with N cards each, then counting the same-rank pairs in the hand. It tests linearity of expectation, probabilities when drawing without replacement, and how the definition of a pair changes the answer.
Statistics & MathOnline Assessment - SIG (Susquehanna)MediumQuantitative TraderExpected Payoff of a Three N-Sided Dice Matching Game
An expected value question about rolling three fair N-sided dice, with different payoffs when all three match, exactly two match, or all differ. It tests counting the outcome classes correctly for a general number of faces and combining them into one expected payoff, including a variant where the all-different outcome costs money.
Statistics & MathOnline Assessment - SIG (Susquehanna)EasyData ScientistFind Expected Spins Until Two Regions Appear
This problem tests knowledge of expected value and geometric distributions by calculating the expected number of trials to observe two distinct outcomes from a discrete probability distribution.
Statistics & MathOnline AssessmentProbabilityExpected ValueGeometric Distribution - SIG (Susquehanna)EasyData ScientistFind a Green Triangle's Weight in a Balanced Mobile
Solve a nested balanced-mobile puzzle and determine the green triangle's weight from a 160-pound total. The worked derivation uses an explicit equal-arm, massless-bar assumption, propagates whole-submobile weights upward, and explains why the left branch alone fixes the answer at 10 pounds.
Statistics & MathOnline Assessment
Roblox
Rubrik
SIG (Susquehanna)