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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 3121–3150 of 9403 results
- DoorDashHardSoftware EngineerResolve a Workplace Conflict
Tests your ability to navigate high-stakes technical or cross-functional disagreements constructively using data, empathy, and active listening to achieve a durable outcome.
Behavioral & LeadershipOnsiteBehavioralLeadershipConflict Resolution - DoorDashMediumSoftware EngineerReview Constant-Time Random Courier Selection and Removal
Maintain dense map indices for uniform random selection and swap-with-last removal, including empty states, concurrency, and complexity checks.
Software Engineering FundamentalsOnsite - DoorDashHardSoftware EngineerScale the cache to a distributed system
This question evaluates a candidate's ability to design and scale a distributed caching system, testing competencies in sharding and consistent hashing, replication and consistency models, request routing, failure detection, cache invalidation, capacity planning, and operational trade-offs for high-throughput, low-latency workloads.
System DesignTechnical Screen - DoorDashMediumSoftware EngineerSelect the best dasher for an order
This problem evaluates algorithmic selection and geometric computation skills—filtering eligible dashers, calculating Euclidean distances, and applying deterministic tie-breaking—within the Coding & Algorithms domain at an implementation-level algorithmic abstraction.
Coding & AlgorithmsOnline Assessment - DoorDashMediumData ScientistShould DoorDash add bicycle dashers?
This problem tests the ability to design an A/B test for a marketplace intervention, identify success metrics, and account for potential cannibalization and external factors in urban delivery.
Analytics & ExperimentationTechnical ScreenA/B TestingMarketplace AnalyticsCausal Inference - DoorDashMediumSoftware EngineerSimulate Constant-Time Random Courier Selection
Design a courier pool data structure that supports adding, removing, and uniformly selecting random courier IDs in average O(1) time.
Coding & AlgorithmsTechnical ScreenData StructuresHash TableArray - DoorDashMediumSoftware EngineerSolve BFS grid delivery routing
This question evaluates proficiency in grid-based graph traversal and shortest-path computation, along with complexity analysis and handling dynamic changes, assessing skills in algorithm design, graph algorithms, and data structures within the Coding & Algorithms domain.
Coding & AlgorithmsTechnical Screen - DoorDashMediumData ScientistSolve multi-part SQL with sliding windows
This question evaluates a candidate's practical SQL data-manipulation skills, including time-based rolling aggregates, distinct counts and deduplication, multi-table joins, revenue aggregation and ranking, and session/streak computations within the Data Manipulation (SQL/Python) domain.
Data Manipulation (SQL/Python)Technical Screen - DoorDashMediumSoftware EngineerSolve string match and DashMart BFS
This question evaluates proficiency with string algorithms and pattern matching, assessing understanding of substring search complexity and algorithm selection within the algorithms and data structures domain, and is commonly asked to verify efficient low-level text-search implementation and time/space trade-off reasoning at a practical implementation level. The "Dash Mart" grid BFS evaluates graph traversal, state-space modeling, and shortest-path reasoning for multi-target collection tasks within graph algorithms and path-finding, and is commonly asked to measure competence in BFS-based search, state encoding and optimization strategies with a focus on practical algorithmic application and performance considerations.
Coding & AlgorithmsTechnical Screen - DoorDashMediumSoftware EngineerSolve tree distance and design file system
This interview question evaluates algorithm design, data structures, correctness, complexity, edge cases, and implementation details in a realistic interview setting. A strong answer for Solve tree distance and design file system states assumptions, handles edge cases, explains trade-offs, and shows how to validate the result clearly.
Coding & AlgorithmsOnsite - DoorDashMediumSoftware EngineerTrack the First Unique Restaurant in a Stream
This problem tests your ability to maintain stream uniqueness using a combination of a hash map and a doubly linked list to ensure constant-time operations.
Coding & AlgorithmsOnsiteHash MapLinked ListDesign - DoorDashMediumSoftware EngineerValidate a Shopping Cart
Implement a shopping cart validation function that checks item availability, consolidates duplicate entries, verifies inventory levels, and ensures order minimums are satisfied.
Coding & AlgorithmsTechnical ScreenHash TableData ValidationBusiness Logic - DoorDashHardAnalytics EngineerWalk Through an ETL Project
This question evaluates an analytics engineer's end-to-end ETL and data engineering competencies, including data ingestion, transformations, data modeling, orchestration, testing, monitoring, backfills, and handling failures or schema changes.
Behavioral & LeadershipTechnical Screen - DoorDashEasyMachine Learning EngineerWalk Through an ML Project
This question assesses the candidate's ability to communicate a full-lifecycle machine learning project, focusing on problem scoping, technical execution, and business impact.
Behavioral & LeadershipTechnical ScreenML LifecycleProduct ThinkingModel Deployment - DoorDashMediumData ScientistWrite SQL for deliveries analytics
This question evaluates SQL data manipulation and analytics skills—specifically aggregation, conditional counting, time-window filtering, joins, and handling of nulls and zero-count periods.
Data Manipulation (SQL/Python)Technical Screen - DoorDashMediumData ScientistWrite SQL for percent and window changes
This question evaluates proficiency with advanced SQL techniques—specifically the use of CTEs and multiple window functions, row-level versus aggregated conditionals, time-windowed aggregations, generation of unit-day series including zero-order days, and correct handling of missing exposure labels for percent and change calculations.
Data Manipulation (SQL/Python)Technical Screen - DoorDashMediumData ScientistWrite SQL to backtest refund policy
This question evaluates advanced SQL data-manipulation and analytics competency, including time-based lateness calculations, window functions (PERCENT_RANK and rolling/partitioned windows), CTEs and joins, aggregation, and monetary-field handling for a policy-simulation scenario.
Data Manipulation (SQL/Python)Technical Screen - DoorDashMediumData ScientistWrite complex SQL on DoorDash data
This question evaluates proficiency in complex SQL querying and data manipulation, including joins across tables, time-based filtering, window functions, null and edge-case handling, aggregations, and integrating promotion and order-event data.
Data Manipulation (SQL/Python)Onsite - DropboxMediumData ScientistAnswer rapid-fire leadership checklist
This question evaluates leadership competencies in privacy decision-making, risk management, stakeholder negotiation, incident prioritization, mentoring, and end-to-end ownership within a data science and operational engineering context.
Behavioral & LeadershipTechnical Screen - DropboxMediumData ScientistCompute max island with constrained flips
This question evaluates understanding of grid-based graph connectivity, connected-component labeling, and algorithmic complexity analysis (time and space) within the Coding & Algorithms domain, emphasizing practical algorithm design for large-scale inputs.
Coding & AlgorithmsTechnical Screen - DropboxMediumSoftware EngineerCompute worst-case guesses for adaptive hangman
This question evaluates algorithmic problem-solving, combinatorial reasoning, and adversarial information-theoretic thinking by requiring modeling of worst-case query strategies for adaptive letter-guessing.
Coding & AlgorithmsOnsite - DropboxMediumSoftware EngineerDescribe Your Most Complex Project
This question evaluates a candidate's communication, leadership, ownership, and problem-solving competencies, specifically probing technical depth in system architecture, trade-offs, collaboration, risk management, and measurable impact.
Behavioral & LeadershipOnsite - DropboxMediumSoftware EngineerDescribe surprising project learnings
This question evaluates reflective project ownership, leadership, decision-making, communication, and the ability to derive actionable lessons from surprising findings in substantial software engineering work.
Behavioral & LeadershipOnsite - DropboxMediumSoftware EngineerDesign a recursive distributed file crawler
This prompt evaluates expertise in distributed systems, asynchronous task orchestration, recursive job scheduling, data modeling for job and file metadata, and reliability concerns such as retries, idempotency, deduplication, and partial failure handling.
System DesignOnsite - DropboxMediumSoftware EngineerDesign an S3-like Object Store
This problem evaluates your ability to design a distributed, highly available, and scalable object storage system capable of handling massive volumes of unstructured data.
System DesignOnsiteDistributed SystemsStorageScalability - DropboxMediumData ScientistDesign enterprise file recommendations under ACLs
This problem tests the ability to design a multi-tenant recommendation system that enforces complex security constraints while maintaining low latency.
Machine LearningTechnical ScreenRecommendation SystemsMulti-tenancySecurity - DropboxMediumSoftware EngineerDesign file-processing API with long-running jobs
This question evaluates a candidate's ability to design HTTP APIs and scalable backend architectures for long-running file-processing jobs, covering competencies in API design, job orchestration, distributed systems, fault tolerance, state persistence, and idempotency.
System DesignOnsite - DropboxMediumData ScientistExplain a project with measurable impact
This question evaluates a data scientist's ability to demonstrate end-to-end project ownership, measurable impact, causal measurement and metric validity, technical design decisions, risk mitigation, scalability reasoning, and management of security/privacy constraints.
Behavioral & LeadershipTechnical Screen - DropboxMediumSoftware EngineerImplement KV Store and Token Bucket
This problem tests your ability to design a thread-safe in-memory key-value store and implement a rate limiter using the token bucket algorithm.
Coding & AlgorithmsOnsiteConcurrencyData StructuresRate Limiting - DropboxMediumSoftware EngineerImplement feedback for word guessing game
This question evaluates a candidate's ability to implement string-processing, frequency-counting, and membership-validation logic to generate exact and misplaced character matches for a word-guessing game.
Coding & AlgorithmsOnsite
DoorDash
Dropbox