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Coding questions · ByteDance
Assign Meetings and Find the Most-Used Room
Practice an interval-scheduling problem where meetings may be delayed and room-number tie rules affect the final count. The prompt tests precise simulation, large-input complexity, integer safety, and careful handling of simultaneous room availability.
Coding questions · Whatnot
Assign Waiting Riders to the Earliest-Arriving Car on Fixed Routes
Cars drive fixed routes over a road map with travel times while riders wait at attractions for a ride to a destination. Assign each rider to the car that reaches their stop first while still visiting their destination later, break ties by car index, and list every car's riders. It tests route timing, indexing and tie handling.
Coding questions · Expedia
Audit and onboard unfamiliar datasets safely
This question evaluates a data scientist's competency in dataset discovery, schema and key verification, profiling for distributions/missingness/timezones/currencies, duplicate and join-inflation detection, event-sequence validation, accurate metric computation, and the design of data-quality tests/data contracts within SQL/Python workflows.
Coding questions · Capital One
Audit flight data quality from metadata
This question evaluates data quality auditing competencies, including validation of timestamps and timezones, detection of label leakage and inconsistent units, provenance and schema enforcement, and hands‑on use of SQL/Python for dataset inspection.
Coding questions · Waymo
Average of a List of Integers, Returning 0 for an Empty List
Write a function that returns the arithmetic mean of a list of integers and returns 0 for an empty list. A warm-up from a timed data science assessment that tests careful handling of the empty case and floating-point division.
Coding questions · Hudson
Ball Position in a Tilting Maze After Timed Tilt Events
Live coding simulation problem: a ball sits in a grid maze on a board that can tilt up, down, left or right or lie flat, and timed events change the tilt. Return the ball's cell at an end time that can be very large. It tests precise timing rules, wall handling and movement code that scales to long time spans.
Coding questions · Siemens
Batch and Pad Variable-Length Vectors with Optional Final-Batch Dropping
Build an ordered vector data pipeline with batch-local right padding, empty-vector handling, and optional dropping of the final incomplete batch.
Coding questions · Rippling
Bill Deliveries with Historical Rates and Deferred Rounding
Bill deliveries with start-time historical rates, duplicate suppression, overlapping jobs, exact sub-cent accumulation, and configurable final half-up or half-even rounding.
Coding questions · Capital One
Block-Building Operations: Check Whether a Free Segment Starts at a Position
Process operations on a number line that either place a block at a position or ask whether a segment of a given length starting at a position is free of blocks, and return the answers as a string of ones and zeros. It tests handling interleaved updates and range checks efficiently over large coordinates.
Coding questions · Amazon
Build a BFS Web Crawler
This question evaluates understanding of breadth-first traversal, URL normalization, domain scoping, duplicate detection, and retry/error handling, measuring algorithmic design and robustness in networked code.
Coding questions · Snowflake
Build a cohort dashboard with Streamlit and SQL
This question evaluates proficiency in cohort analysis using SQL window functions, time-based aggregation, ARPU calculation, and integration of data querying with a Streamlit visualization front end, including handling timezones and data-quality checks.
Coding questions · XPeng
Build a Least-Recently-Used Store
This question evaluates understanding of caching and eviction policies and practical proficiency with data structures such as hash tables and ordered collections for tracking and updating recency.
Coding questions · Sigmacomputing
Build a Pivot Table Aggregator
This question evaluates a candidate's ability to implement data aggregation and efficient lookup structures, focusing on grouping, associative aggregations, and maintaining intermediate state for derived metrics.
Coding questions · Uber
Build a Quadtree and Analyze a Graph
This question evaluates skills in spatial data structures and recursive tree construction (building a quadtree) as well as graph analysis using traversal and cycle/safety detection to identify nodes that necessarily reach terminal nodes.
Coding questions · Uber
Build a QuadTree From a Grid
This question evaluates understanding of spatial data structures and recursive divide-and-conquer techniques by compressing uniform regions into a QuadTree representation.
Coding questions · Snowflake
Build a Top-Down Reporting Forest from Employee-Manager Pairs
Given employee-to-manager pairs of integer IDs, build the top-down reporting forest with every top-level manager as a root, and return it as a preorder listing of IDs and depths. Tests finding the roots, building child lists, deterministic sibling ordering, and handling long reporting chains.
Coding questions · Square
Build a Trust-Aware BIN Database
Build an in-memory card-prefix database that resolves brand and card type independently across overlapping writes. Practice combining longest-prefix matching with trust and recency rules while preserving omitted fields and supporting heavy lookup traffic.
Coding questions · ByteDance
Build a validated add-sub calculator
This question evaluates skills in string parsing, tokenization, input validation, and safe integer arithmetic handling, with emphasis on enforcing format rules such as operator placement, prevention of leading zeros, and 32-bit signed integer bounds.
Coding questions · Chicago Trading Company
Build an Ordered Latest-Quote Container
Build an insertion-ordered container that stores only the latest quote for each stock symbol. Support expected O(1) push, pop, and size operations while updating bid and ask values without changing a symbol's original position and safely rejecting malformed commands.
Coding questions · Amazon
Build DiD dataset with SQL
This question evaluates proficiency in SQL-based data manipulation and panel construction for staggered-adoption difference-in-differences, testing skills in handling adoption dates, event-time calculations, boundary conditions, and aggregation in the Data Manipulation (SQL/Python) domain.
Coding questions · Nextdoor
Build Ranked Feed With Photo Batching
This question evaluates algorithmic reasoning and data manipulation skills, including stable sorting, grouping/batching, and merging of ranked items while preserving ordering invariants.
Coding questions
Build SQL pivot with lookups and currency conversion
This question evaluates proficiency in data manipulation using SQL or SQL-like Python transforms, covering point-in-time currency conversion, temporal joins for FX lookups, joins to enrich product/customer metadata, aggregation and pivot-style reporting, ranking, and data-quality checks for missing FX.
Coding questions · Amazon
Calculate 7-Day Rolling Average for Energy Consumption
This question evaluates programming fluency in numerical data processing and algorithmic implementation for computing moving averages and handling edge cases in time-series sequences, and it applies to Data Scientist roles while falling under the Coding & Algorithms category.
Coding questions · Pinterest
Calculate 95% Bootstrap Confidence Interval for Order Values
This question evaluates a data scientist's competence in statistical inference using bootstrap resampling, proficiency with numerical computing for large sample operations, and attention to performance optimization.