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Coding questions
Explore algorithm tutorials, coding and system design questions, interview experiences, and computer science study guides.
1,899 resources · Page 23 of 80
Coding questions · Amazon
Create Monthly Revenue Report for Each Department
This question evaluates proficiency in SQL data transformation and aggregation, specifically the ability to pivot row-level transactional revenue into a columnar monthly report and handle schema alignment for reporting.
Coding questions · Robinhood
Create OHLC Aggregates from Tick Data in Python
This question evaluates a candidate's ability to perform time-series bucketing and OHLC aggregation from tick data, testing skills in data parsing, stateful aggregation, and handling missing-interval forward-filling; it falls under Data Manipulation (SQL/Python) and assesses practical application rather than purely conceptual understanding.
Coding questions · Amazon
Create SQL Queries for Sales and Customer Analysis
This question evaluates proficiency in SQL-based data manipulation, covering aggregation and dispersion metrics, null handling, relational joins, and window functions for ranking customers.
Coding questions · Bloomberg
Create SQL report of top extensions by weekday
This question evaluates a candidate's ability to perform advanced SQL data manipulation and aggregation, encompassing date filtering, string extraction from URL paths, frequency counting with tie resolution, and pivoting results by weekday.
Coding questions · CVS Health
Create Views, Insert, and Update Correctly
This question evaluates SQL data-manipulation competencies including view creation, aggregate joins, INSERT/UPDATE operations, and reasoning about temporal effects on computed aggregates such as historical customer spend.
Coding questions · Capital One
Critique and Test Python Preprocessing Utilities Effectively
This question evaluates a candidate's ability to review and critique Python preprocessing utilities, covering competencies in software design patterns (fit/transform separation), coding style and import hygiene, and unit-test specification for data-science pipelines.
Coding questions · DoorDash
Dasher Daily Pay from Order Events with Double Rate in Peak Windows
A coding problem that computes a delivery driver's daily pay from accept and deliver events, where the per-minute rate scales with the number of orders in progress. Peak windows double the rate, so active periods that cross a window boundary must be split exactly, and the total is returned in integer cents.
Coding questions · Apple
Days Until Poison Stops Spreading in a Plant Grid Under a K-of-8-Neighbors Rule
A grid simulation coding question: plants are healthy or poisoned, and each day every healthy plant with at least k poisoned plants among its eight neighbors becomes poisoned. It asks how many days pass until no new plant is poisoned, testing simultaneous-update semantics, edge cells, and a solution that runs in time linear in the grid size.
Coding questions · DoorDash
Debug a driver assignment bug
This question evaluates debugging, root-cause analysis, unit/integration test design, observability, and system-resilience competencies within the Coding & Algorithms domain, emphasizing practical skills in reproducing failures, isolating defects, and implementing targeted fixes.
Coding questions · TikTok
Debug a Hive insert query
This question evaluates a candidate's ability to debug Hive INSERT/SELECT operations, focusing on schema and column alignment, data types and casts, partition handling, file formats/SerDe, ACID/transactional constraints, and syntax or reserved keyword issues.
Coding questions · TikTok
Debug a Hive query
This question evaluates a candidate's ability to debug and validate Hive SQL queries, assessing competencies in identifying logical errors (incorrect join conditions, aggregation and window function misuse, filters and partition predicates), validating results with test cases, and reasoning about performance optimizations.
Coding questions · TikTok
Debug a Hive Query for DAU
This question evaluates proficiency in Hive/SQL query formulation, data partitioning and pruning, join and aggregation semantics, timestamp handling, and performance tuning for large-scale analytics.
Coding questions · DoorDash
Debug and refactor a legacy module
This question evaluates debugging, refactoring, naming and exception handling, input validation, code structure, and concurrency-safety design skills within a legacy codebase, requiring both hands-on code changes and higher-level reasoning about immutability, confinement, synchronization, and concurrent data structures.
Coding questions · Capital One
Debug and test a Python function in venv
This question evaluates understanding of Python runtime semantics (mutable default arguments, in-place list mutation during iteration), debugging and unit-testing practices, virtual environment and packaging workflows, and CI/tooling considerations.
Coding questions · DoorDash
Debug round-robin, DashMap, and simple cache
This question evaluates skills in concurrent programming and stateful selection logic (round-robin load balancing), data structure invariants and debugging (custom hash map hashing vs equality, collision resolution, resizing and iterator correctness), simple in-memory caching strategies with TTL or size-based eviction, and unit test design.
Coding questions · Home Depot
Debug SQL join that drops rows
This question evaluates understanding of SQL joins, filtering interactions, aggregation, and troubleshooting data discrepancies when combining sales, sale_items, products, and promotions tables.
Coding questions · DoorDash
Debug using logs and allocate tasks
This question evaluates a candidate's skill in log-driven debugging, production incident investigation, and cross-functional task allocation, covering competencies such as structured and contextual logging, correlation identifiers, noise reduction, minimal reproducibility, feature-flagged isolation, triage coordination, hypothesis tracking, root-cause confirmation, regression prevention, and blameless postmortems. It is commonly asked to assess operational troubleshooting and teamwork under production uncertainty within the Coding & Algorithms category, testing practical application of debugging techniques alongside conceptual understanding of incident management and process-level coordination.
Coding questions · Glean
Decide If a Passenger Can Reach a Station Using Time-Indexed Train Routes and Transfers
Given trains described as time-indexed lists of stations, decide whether a passenger starting at one station at time zero can reach another by riding, waiting and transferring. Tests modeling station and time as search states, handling waits and same-time transfers, and breadth-first search over a time-expanded graph.
Coding questions · Waymo
Decide If a Vehicle Is Ready to Go from Open/End Maintenance Events
Given a vehicle maintenance log of open and end events with timestamps and maintenance types such as oil or brake, decide whether the vehicle is ready to go. The problem tests chronological event processing with a stable tie rule, per-type state tracking, and detecting unmatched ends, overlapping opens, and tasks left open.
Coding questions · Meta
Decide palindrome within k deletions
This interview question evaluates algorithm design, data structures, correctness, complexity, edge cases, and implementation details in a realistic interview setting. A strong answer for Decide palindrome within k deletions states assumptions, handles edge cases, explains trade-offs, and shows how to validate the result clearly.
Coding questions · Amazon
Decide reachability with buses and limited walking
This question evaluates the ability to combine graph reachability with geometric distance constraints, testing competencies in graph algorithms, Manhattan-distance reasoning, and constrained-path modeling within the Coding & Algorithms domain.
Coding questions · Oracle
Decide Whether a Parenthesis String With Star Wildcards Can Be Balanced
Decide whether a string of parentheses and stars can become a balanced parenthesis string when each star may independently act as an opening parenthesis, a closing parenthesis or an empty string. Tests reasoning over many possible replacements at once and edge cases with unmatched parentheses near either end.
Coding questions · Mercor
Decide whether every car can park given preferred spots and forward-only overflow
A coding question about cars arriving one at a time on a one-way street, each trying its preferred parking spot first and moving only forward when that spot is taken. You decide whether every car manages to park, which tests careful rule-following and efficient handling of spot occupancy for large inputs.
Coding questions · Sealth
Decode Ambiguous Morse Messages
This question evaluates string parsing, pattern matching, and combinatorial decoding skills using a Morse-to-letter mapping, covering both deterministic separator handling and enumeration of ambiguous letter partitions.