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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 31–60 of 3640 results
- AdobeMediumSoftware EngineerReturn a Binary Tree in Level Order
Return a binary tree's values grouped by depth in level order while preserving left-to-right order within each level. Handle empty, repeated-value, skewed, and very large trees without changing the requested nested output shape.
Coding & AlgorithmsOnsite - AdobeMediumData ScientistSolve SQL and Python Data Manipulation Tasks
This question evaluates proficiency in SQL event-log aggregation and basic Python data-structure transformations, assessing competencies such as counting distinct users, identifying frequent event types, and performing dictionary/list/string manipulations.
Data Manipulation (SQL/Python)Onsite - AdobeEasyData ScientistUnderstand P-Value's Role in Product Decision-Making
This interview question evaluates statistical assumptions, formulas, estimation strategy, uncertainty, edge cases, and interpretation in a realistic interview setting. A strong answer for Understand P-Value's Role in Product Decision-Making states assumptions, handles edge cases, explains trade-offs, and shows how to validate the result clearly.
Statistics & MathOnsite - AffirmHardSoftware EngineerCompute Balances and Minimize Settlements
Tests transaction aggregation into net balances and combinatorial optimization (backtracking/bitmask DP) to find the minimum number of settlement transfers needed to clear all debts.
Coding & AlgorithmsOnsiteDynamic ProgrammingBacktrackingBitmask - AffirmEasySoftware EngineerDesign a Ticketmaster-like ticketing system
This question tests your ability to design a high-concurrency booking system, focusing on preventing double-bookings, managing seat holds, and ensuring system availability during high-traffic events.
System DesignOnsiteConcurrencyDistributed SystemsCaching - AffirmHardSoftware EngineerDesign an A/B Testing Platform
Design a high-scale, low-latency experimentation and A/B testing platform capable of deterministic user bucketing, high-throughput exposure and metric ingestion, and automated statistical reporting.
System DesignOnsitesystem-designdistributed-systemsdata-engineering - AffirmMediumSoftware EngineerDiscuss team fit and leadership with manager
Discuss team fit and leadership with manager evaluates behavioral evidence, ownership, communication, trade-offs, and measurable outcomes in a realistic interview setting. A strong answer states assumptions, handles edge cases, explains trade-offs, and shows how to validate the result clearly.
Behavioral & LeadershipOnsite - AffirmEasySoftware EngineerImplement an LRU cache
This question tests the ability to combine a hash map and a doubly linked list to achieve constant-time performance for both data retrieval and update operations in a cache.
Coding & AlgorithmsOnsiteHash MapLinked ListDesign - AffirmMediumSoftware EngineerImplement and debug event filtering in Python
This question evaluates proficiency in data manipulation and algorithmic reasoning in Python, covering event filtering, stable sorting, deduplication by identifier, timestamp windowing, and analysis of time and space complexity.
Data Manipulation (SQL/Python)Onsite - AirbnbMediumSoftware EngineerAllocate an Order from the Oldest Inventory Batches
Implement a function to allocate an order across inventory batches using FIFO (oldest timestamp first, with batch ID tie-breaker), returning allocation details and any unfilled quantity without mutating the input.
Coding & AlgorithmsOnsitesortinggreedyarrays - AirbnbMediumSoftware EngineerAllocate refund across payments
This question evaluates algorithm design and data-structure selection skills, focusing on greedy allocation, ordering by priority and recency, aggregation of transaction amounts, and analysis of time complexity.
Coding & AlgorithmsOnsite - AirbnbMediumData EngineerCalculate the Median House Price in Each City
Tests your ability to compute grouped medians in PostgreSQL, properly handling even and odd row counts, duplicate price values, and numeric precision.
Data Manipulation (SQL/Python)Onsitesqlpostgresqlaggregations - AirbnbMediumSoftware EngineerCompute board-game score from regions
This problem tests your ability to identify connected components in a 2D grid using graph traversal (BFS/DFS) and aggregate properties associated with those components.
Coding & AlgorithmsOnsiteGraph TraversalBFSDFS - AirbnbHardSoftware EngineerCount Consecutive Positive Integer Sums
Count representations of a positive integer as one or more consecutive positive integers, including the one-term representation. Derive the arithmetic condition for each sequence length and use a square-root bound rather than testing every possible starting value.
Coding & AlgorithmsOnsite - AirbnbMediumSoftware EngineerDescribe a cross-functional project you’re proud of
This question evaluates cross-functional collaboration, leadership, stakeholder alignment, conflict resolution, project ownership, and the ability to articulate technical and product decisions along with measurable impact.
Behavioral & LeadershipOnsite - AirbnbMediumSoftware EngineerDescribe a flagship project’s architecture and tradeoffs
This question evaluates leadership and ownership along with system architecture and trade-off analysis, assessing competencies in end-to-end technical design, stakeholder communication, implementation decisions, and metrics-driven impact.
Behavioral & LeadershipOnsite - AirbnbMediumMachine Learning EngineerDesign User Embedding Semantic Search
This question evaluates competency in ML system design for recommendation and semantic retrieval, covering user and listing representation learning, two-stage retrieval and ranking architectures, training objectives and label design, bias correction from interaction logs, and evaluation and experimentation practices.
ML System DesignOnsite - AirbnbMediumMachine Learning EngineerDesign a Family-Friendly Listing Classifier
This question evaluates proficiency in machine learning system design, including problem formulation tied to product objectives, labeling strategy, feature engineering, model selection, evaluation metrics, robustness to adversarial labels, fairness considerations, and cold-start handling.
ML System DesignOnsite - AirbnbMediumSoftware EngineerDesign a Reliable Scheduler for Payment Jobs
Tests candidate's ability to design a mission-critical, fault-tolerant job scheduler for payment processing, focusing on lease claiming, idempotency, race condition handling, and reconciliation.
System DesignOnsitesystem-designdistributed-systemspayments - AirbnbHardBackend EngineerDesign a Rental Marketplace Backend
This problem tests your ability to design a distributed, high-scale rental marketplace platform, focusing on concurrency control for bookings, efficient geo-spatial searching, and data consistency.
System DesignOnsiteDistributed SystemsConcurrencyGeo-spatial - AirbnbMediumSoftware EngineerDesign a booking system
This question tests the ability to design a distributed reservation system that handles high concurrency, prevents double-booking, and ensures data consistency at scale.
System DesignOnsiteConcurrencyDatabaseDistributed Systems - AirbnbHardSoftware EngineerDesign a dynamic rental pricing system
This question evaluates skills in production machine learning system design for pricing, including problem formulation, data and feature engineering, modeling and uncertainty management, online inference and scalability, experimentation and guardrails, and considerations like fairness and cold-start handling.
ML System DesignOnsite - AirbnbHardSoftware EngineerDesign a group chat system
Airbnb's onsite system design round asks you to design the backend for a real-time group chat and messaging system: 1:1 and group conversations, near-real-time delivery, accurate unread counts, and full paginated history at roughly 1B messages a day and 5M concurrent connections. A complete answer covers the guarantees, APIs, data model and partitioning, write path and ordering, WebSocket fan-out and presence, offline delivery and multi-device sync, unread counts, membership changes, failure modes and observability. This walkthrough gives a corrected end-to-end reference answer for every part, including the trade-offs interviewers probe.
System DesignOnsite - AirbnbHardSoftware EngineerDesign a hot-listing waitlist API
Design a hot-listing waitlist API 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 DesignOnsite - AirbnbHardSoftware EngineerDesign a real-time chat system with hot groups
This problem tests your ability to design a distributed, low-latency messaging system that handles massive fan-out and identify trending group activities.
System DesignOnsiteDistributed SystemsWebSocketsCaching - AirbnbHardSoftware EngineerDesign a scalable consumer feature
This question evaluates a candidate's ability to design large-scale recommendation systems, covering system architecture, real-time serving and offline pipelines, personalization and ML modeling (candidate generation and ranking), data modeling/feature stores, caching and storage, monitoring, experimentation, and privacy/compliance skills.
System DesignOnsite - AirbnbHardSoftware EngineerDesign an A/B Testing Platform
Design an A/B testing platform with deterministic assignment, versioned experiment configuration, exposure logging, outcome attribution, and trustworthy analysis. Separate the latency-sensitive serving path from asynchronous metrics, support gradual ramps and overlapping tests, and detect bias, event loss, skew, and sample-ratio mismatch.
System DesignOnsite - AirbnbHardData ScientistDesign and assess an A/B test
This problem tests your ability to design a statistically sound A/B test for a marketplace platform, including metric selection, power analysis considerations, and handling potential interference effects.
Analytics & ExperimentationOnsiteA/B TestingExperimental DesignMetrics - AirbnbHardSoftware EngineerDesign multi-currency pricing end-to-end
This question evaluates understanding of multi-currency pricing and payments, covering currency selection UX, storage versus presentation currency, exchange-rate sourcing and locking, rounding and localization, tax and fee modeling, caching and cross-channel consistency, and API and data-model design in a distributed marketplace.
System DesignOnsite - AirbnbMediumSoftware EngineerDesign mutable sum-tree with fast queries
This question evaluates proficiency in designing dynamic data structures for mutable rooted trees, including maintenance of subtree sums, parent/child link management, and analysis of update and query complexities within the Coding & Algorithms domain; it emphasizes practical application of algorithmic design coupled with conceptual understanding of invariants and amortized complexity. It is commonly asked in technical interviews because it probes reasoning about correctness and performance under mutations, handling edge cases such as subtree deletion and reattachment, and the ability to specify algorithmic approaches and complexity guarantees rather than implementation details.
Coding & AlgorithmsOnsite
Adobe
Affirm
Airbnb