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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 1231–1260 of 4616 results
- CoinbaseEasyData ScientistModel Feature Adoption Probability for Users
This interview question evaluates statistical assumptions, formulas, estimation strategy, uncertainty, edge cases, and interpretation in a realistic interview setting. A strong answer for Model Feature Adoption Probability for Users states assumptions, handles edge cases, explains trade-offs, and shows how to validate the result clearly.
Statistics & MathTechnical Screen - CoinbaseMediumSoftware EngineerPaginate forward and backward through results
This question evaluates understanding of pagination mechanics, cursor/token design, array indexing, and state management for bidirectional (forward and backward) navigation.
Coding & AlgorithmsTechnical Screen - CoinbaseHardSoftware EngineerPick Mempool Transactions for a Block with Parent Dependencies and CPFP
A multi-part coding problem about filling a block of capacity 100 from a large, unsorted mempool of transactions with fees and sizes, where speed matters more than optimality. Later parts add parent transactions that must be included first, child-pays-for-parent across multi-level chains, and an optional minimum fee for a new child.
Software Engineering FundamentalsTechnical Screen - CoinbaseHardData ScientistSolve the 12-coin balance puzzle
This question evaluates understanding of combinatorial reasoning, information theory, and decision-tree construction for identifying a single counterfeit coin and whether it is heavier or lighter using constrained balance-scale observations.
Statistics & MathTechnical Screen - CollegevineMediumSoftware EngineerFind the Highest-Cost Top-Level Job
This question evaluates the ability to process hierarchical JSON data, aggregate durations across tree-structured job relationships, and reason about robustness and scalability concerns such as malformed input handling and performance for large datasets.
Coding & AlgorithmsTechnical Screen - Color HealthMediumSoftware EngineerBuild and Review an Employee Expense Reimbursement Application
This problem tests your ability to design a simple RESTful API and implement core CRUD operations with server-side validation for an expense tracking system.
Software Engineering FundamentalsTechnical ScreenAPI DesignCRUDValidation - CommureMediumSoftware EngineerDesign Monthly Artist Payouts from Streaming Counts
Design a monthly artist-payout system that turns valid streaming events into reproducible obligations and idempotent external payments. The answer covers event deduplication, period closure, payout versions, timeout ambiguity, outbox delivery, provider reconciliation, late adjustments, and auditable financial state.
System DesignTechnical Screen - CommureHardSoftware EngineerFilter People by Optional Criteria
Implement stable filtering for person records across optional inclusive age and salary bounds plus an optional occupation set. Every enabled criterion must match, disabled bounds use None, and neither the input list nor its records may be mutated.
Coding & AlgorithmsTechnical Screen - CommureMediumSoftware EngineerPresent Your Background and Respond to an AI-Use Concern
This exercise evaluates your ability to provide a structured professional narrative, demonstrate technical depth through project ownership, and maintain poise when confronted with a challenging, ethical, or unexpected behavioral probe.
Behavioral & LeadershipTechnical ScreenBehavioralCommunicationEthics - ConfluentMediumSoftware EngineerAnswer standard behavioral prompts
This set of behavioral prompts evaluates ownership, leadership, communication, judgment, accountability, resilience, and time-management competencies for software engineers.
Behavioral & LeadershipTechnical Screen - ConfluentHardSoftware EngineerDesign a distributed key-value store at scale
Design a distributed key-value store at scale evaluates requirements, scale assumptions, API/data design, architecture, trade-offs, failure modes, and rollout in a realistic interview setting. A strong answer states assumptions, handles edge cases, explains trade-offs, and shows how to validate the result clearly.
System DesignTechnical Screen - ConfluentHardSoftware EngineerDesign a temporary email service
This question evaluates a candidate's ability to design scalable, highly available, and privacy-focused email ingestion systems, probing competencies in distributed systems, networking (SMTP/MX), storage lifecycle management, rate limiting, security/privacy, and observability.
System DesignTechnical Screen - ConfluentHardSoftware EngineerExplain variadic functions
Explain variadic functions evaluates requirements, assumptions, structured reasoning, trade-offs, and verification in a realistic interview setting. A strong answer states assumptions, handles edge cases, explains trade-offs, and shows how to validate the result clearly.
Software Engineering FundamentalsTechnical Screen - ConfluentMediumSoftware EngineerImplement tail N lines
Confluent software-engineer technical-screen coding question: implement tail(path, N) to print the last N lines of a possibly multi-GB file or an unbounded stream without loading it into memory. It tests a backward block scan for seekable files versus an O(N) ring buffer for non-seekable streams, plus correct handling of \n/\r\n/\r newlines, UTF-8 multibyte characters, missing trailing newlines, and extremely long lines, with follow-ups on tail -f, log rotation/truncation, and the -c last-N-bytes option.
Coding & AlgorithmsTechnical Screen - ConfluentEasySoftware EngineerProcess pod logs with global increments and pop-min
This problem tests your ability to manage a collection of values under global update operations while maintaining the ability to efficiently extract the minimum value.
Coding & AlgorithmsTechnical ScreenHeapsData StructuresAlgorithms - ConfluentMediumSoftware EngineerSolve constrained monster traversal
Solve constrained monster traversal evaluates algorithm design, data structures, correctness, complexity, edge cases, and implementation details in a realistic interview setting. A strong answer states assumptions, handles edge cases, explains trade-offs, and shows how to validate the result clearly.
Coding & AlgorithmsTechnical Screen - CoreweaveEasySoftware EngineerBuild a Resilient Concurrent Python CLI for Local-Service Lookups
Design a Python CLI for serial-number lookups with timeout, HTTP, and JSON handling, bounded thread-pool concurrency, and ordered results.
Software Engineering FundamentalsTechnical Screen - CoreweaveMediumSoftware EngineerCoordinate Basic Threads and Inspect Them on Linux
Use basic Python threading primitives for bounded concurrent function calls, exception capture and joining, then inspect native threads with Linux tools.
Software Engineering FundamentalsTechnical Screen - CoreweaveMediumSoftware EngineerDesign a predicate structure and filter records with comparison, AND and OR
Design a data structure for predicates that combine greater-than and less-than comparisons with AND and OR, then implement filter(data, predicate) to return the matching items. Tests recursive structure design, extensibility to new operators, evaluation with early exit, and handling of missing fields and type mismatches.
Software Engineering FundamentalsTechnical Screen - CortexMediumSoftware EngineerParse API JSON and print org chart
This question evaluates HTTP and JSON parsing, CSV processing, hierarchical data modeling, sorting, and algorithmic efficiency for building and printing an organizational chart.
Coding & AlgorithmsTechnical Screen - CostcoMediumSoftware EngineerDebug a Google Cloud Web App Where 80% of Users See Only a Loading Spinner
A production debugging scenario: a web app deployed on Google Cloud loads for only 20% of users while the other 80% see a loading spinner forever. It tests a systematic walkthrough that scopes the failure, gathers browser and server evidence, and tests explanations for the split one at a time.
Software Engineering FundamentalsTechnical Screen - CoupangEasySoftware EngineerFind the Closest Value in a Binary Search Tree
This question tests your ability to traverse a binary search tree efficiently by leveraging its ordering property to find the node value closest to a given target number.
Coding & AlgorithmsTechnical ScreenBinary Search TreeBinary TreeTree Traversal - CoupangMediumData ScientistMonthly Cohort Retention
This question tests the ability to transform raw user activity logs into a cohort retention matrix by calculating the time elapsed between a user's first interaction and subsequent activity.
Data Manipulation (SQL/Python)Technical ScreenSQLRetentionCohort Analysis - CoupangMediumData ScientistPredicting the Next Elevator Call Location
This question tests the ability to design a spatio-temporal forecasting system to predict future elevator call locations, focusing on feature engineering, model selection, and handling data sparsity.
Machine LearningTechnical ScreenTime-SeriesFeature EngineeringSpatio-Temporal - CoupangMediumData ScientistReserving an Elevator for Food Deliveries
This question evaluates your ability to design an A/B test for an operational policy change in a high-traffic environment, focusing on cluster randomization, metric selection, and handling network effects.
Analytics & ExperimentationTechnical ScreenA/B TestingExperiment DesignMetrics - CourseraHardSoftware EngineerImplement Plurality and Runoff Voting
This question evaluates understanding of voting algorithms, tie-breaking rules, ballot processing, and correctness under edge cases such as incomplete or exhausted ballots, and is commonly asked to assess algorithmic implementation, state simulation, and careful handling of corner cases in interview settings.
Coding & AlgorithmsTechnical Screen - CourseraHardBackend EngineerImplement Popular and Ranked Voting
This question evaluates algorithmic implementation skills and understanding of voting systems, including aggregation of first-place preferences and the conceptual mechanics of elimination-based ranked-choice counting.
Coding & AlgorithmsTechnical Screen - Credit GenieMediumSoftware EngineerImplement FastAPI CRUD endpoints from skeletons
This question evaluates a candidate's ability to implement RESTful CRUD endpoints with FastAPI, focusing on API contract consistency, HTTP status codes and idempotency, input validation and exception handling, and unit testing.
Software Engineering FundamentalsTechnical Screen - Credit GenieMediumSoftware EngineerImplement and analyze number-pattern function
This question evaluates algorithmic thinking and implementation skills related to string construction, time and auxiliary space complexity analysis, and handling boundary/edge-case off-by-one errors.
Coding & AlgorithmsTechnical Screen - Credit GenieMediumSoftware EngineerIntroduce yourself and show mission alignment
This question evaluates behavioral and leadership competencies including communication, mission alignment, expectation-setting, and collaborative API/interface ownership within an ML engineering context.
Behavioral & LeadershipTechnical Screen
Coinbase
Confluent
Coreweave
Coupang