Databricks interview questions

Showing 91–120 of 122 results

• Implement Resilient Autocomplete Data FetchingMedium

  Implement resilient autocomplete fetching with a quiet period, bounded retries, newest-query precedence, and reuse of recent results. Cover empty input, out-of-order responses, cancellation during waits and requests, error classification, freshness and capacity policies, unmount safety, accessibility, shared requests, and responsive ranking.

  DatabricksFrontend EngineerSoftware Engineering FundamentalsOnsite
• Implement Simple Linear Regression with Gradient Descent from ScratchMedium

  Write simple linear regression trained with gradient descent from scratch, choosing the loss, learning rate and stopping rule yourself. Tests deriving the gradients correctly, writing a runnable training loop, understanding feature scaling and convergence, and verifying results against a closed-form fit.

  DatabricksMachine Learning EngineerMachine LearningOnsite
• Implement Snapshot Iterator Without Order GuaranteesMedium

  This question evaluates data-structure design and iterator semantics—specifically snapshot iteration over a mutable, set-like collection without order guarantees—and tests skills in implementing mutation-isolated iteration and analyzing time and space complexity; it belongs to the Coding & Algorithms domain and emphasizes practical implementation.

  DatabricksSoftware EngineerCoding & AlgorithmsTechnical Screen
• Implement a Concurrent Buffered File LoggerMedium

  Design and implement a thread-safe, buffered logger that aggregates concurrent writes across multiple threads and flushes them to disk efficiently with documented ordering guarantees.

  DatabricksSoftware EngineerSoftware Engineering FundamentalsOnsite
• Implement a Snapshot Set IteratorHard

  This question evaluates understanding of set data structures, iterator and snapshot semantics, and the ability to reason about time and space complexity when providing stable views over mutable collections.

  DatabricksSoftware EngineerCoding & AlgorithmsTechnical Screen
• Implement a Tic-Tac-Toe game APIHard

  This problem tests your ability to design a state-tracking system for an n x n Tic-Tac-Toe board that allows for constant-time move validation and win detection.

  DatabricksSoftware EngineerCoding & AlgorithmsOnsite
• Implement a rate-limited hit counterMedium

  This question evaluates a candidate's understanding of designing efficient time-windowed data structures and algorithmic analysis, including space-time trade-offs and amortized complexity.

  DatabricksSoftware EngineerCoding & AlgorithmsOnsite
• Implement a sliding-window hit counterMedium

  This question evaluates understanding of time-based data structures and algorithms for sliding-window counters, including fixed-size array bucketing, handling timestamp collisions within buckets, refactoring for reuse, and time/space complexity analysis.

  DatabricksSoftware EngineerCoding & AlgorithmsTechnical Screen
• Implement a snapshotable set with iteratorsMedium

  This question evaluates understanding of persistent/versioned data structures, iterator semantics, concurrency control, and complexity-aware design for mutable sets, and is categorized under Coding & Algorithms.

  DatabricksSoftware EngineerCoding & AlgorithmsOnsite
• Implement an Alternating Tic-Tac-Toe GameHard

  This problem tests your ability to design a robust state machine for a board game, focusing on efficient win-condition checking and clean API design.

  DatabricksSoftware EngineerCoding & AlgorithmsTechnical Screen
• Implement lazy array and KV storeMedium

  This problem tests your ability to implement lazy computation using function composition and design a stateful data structure with metadata tracking.

  DatabricksSoftware EngineerCoding & AlgorithmsOnsite
• Implement run-length encoding and decodingMedium

  This question evaluates proficiency in string manipulation and encoding algorithms, specifically run-length encoding and decoding, along with attention to edge cases such as empty inputs and single-character runs and correct handling of repetition counts.

  DatabricksSoftware EngineerCoding & AlgorithmsOnsite
• Implement streaming RLE and bit-packed codecHard

  This question evaluates understanding of data compression algorithms, bit-level manipulation, two's‑complement integer representation, streaming algorithm design, and encoder/decoder state management for 32-bit signed integers.

  DatabricksSoftware EngineerCoding & AlgorithmsOnsite
• Integer Set with O(1) Snapshot Iterators Unaffected by Later ChangesMedium

  Design a set of integers with amortized constant-time add and remove whose iterators capture the exact contents at creation time without copying, stay independent of later changes and of each other, and fit in linear total space. Also compares a shared history log with per-key logs.

  DatabricksSoftware EngineerSoftware Engineering FundamentalsOnsite
• Lowest-Price Book Aggregator Fanning Out to Hundreds of Async BookstoresMedium

  Design a middleman service that takes an ISBN, bid price and payment method, queries several hundred asynchronous bookstores for the lowest price, and then orders, returns the price or reports no stock. Deep dives cover partial results and circuit breakers, caching against thundering herds, and order-and-charge consistency.

  DatabricksSoftware EngineerSystem DesignOnsite
• Optimal Commute: Nearest Transit Distance in a City GridMedium

  Tests the ability to solve multi-source shortest path problems on a grid using multi-source Breadth-First Search (BFS). Evaluates graph traversal efficiency, boundary checking, and handling of impassable terrain.

  DatabricksSoftware EngineerCoding & AlgorithmsTechnical Screen
• Optimize a SQL query plan treeHard

  This problem tests your ability to manipulate an Abstract Syntax Tree (AST) representing a relational query plan to reduce data processing costs through predicate pushdown and projection pruning.

  DatabricksSoftware EngineerCoding & AlgorithmsTechnical Screen
• Partition a Target String by Source SubstringsMedium

  Determine the minimum number of contiguous substrings from a source string required to reconstruct a target string.

  DatabricksSoftware EngineerCoding & AlgorithmsOnsite
• Path Between Two Preorder-Numbered Nodes of an Implicit Fibonacci TreeMedium

  Given the order of a recursively defined Fibonacci tree and two nodes labeled by preorder number, return the path between them without building a tree that can hold trillions of nodes. Tests recursive subtree-size reasoning, implicit tree navigation and 64-bit index arithmetic.

  DatabricksSoftware EngineerCoding & AlgorithmsOnsite
• Present a Technical Project Under Active Follow-UpHard

  This question assesses a candidate's ability to articulate the architecture, personal impact, and technical decision-making process behind a complex engineering project while navigating intense scrutiny.

  DatabricksSoftware EngineerBehavioral & LeadershipOnsite
• Referral Credit Tracker with Indirect ReferralsMedium

  Build a referral credit tracker with account creation, threshold queries, deterministic ordering, and correct credit propagation through indirect referrals.

  DatabricksSoftware EngineerCoding & AlgorithmsOnsite
• Relate coefficients under linear feature transformationEasy

  This question tests the relationship between regression coefficients when predictors undergo linear transformations, specifically focusing on scaling and centering transformations.

  DatabricksData ScientistStatistics & MathTechnical Screen
• Report the Winner After Every Move on an n x n Tic-Tac-Toe BoardMedium

  Process a sequence of alternating tic-tac-toe moves on an n x n board and report, after every move, whether player 1 or player 2 has just completed a full row, column, main diagonal or anti-diagonal. Tests efficient incremental win detection, diagonal indexing and correct handling of draws.

  DatabricksSoftware EngineerCoding & AlgorithmsOnsite
• Retrieve and Rerank Tables and Notebooks for a Data-Aware Coding AgentMedium

  Design the retrieval system that lets an internal coding agent find the right tables and notebooks to answer data questions. Tests what to index for each asset type, hybrid retrieval plus reranking, handling noisy or stale assets, access control, and metric design from retrieval to final answers.

  DatabricksMachine Learning EngineerML System DesignOnsite
• Share background, conflicts, and proud project detailsMedium

  This interview question evaluates behavioral evidence, ownership, communication, trade-offs, and measurable outcomes in a realistic interview setting. A strong answer for Share background, conflicts, and proud project details states assumptions, handles edge cases, explains trade-offs, and shows how to validate the result clearly.

  DatabricksSoftware EngineerBehavioral & LeadershipHR Screen
• Single-Machine Cache with WAL Persistence, Sharded Locks and LRUMedium

  Design and write pseudocode for a single-machine in-memory cache behind a web service, then add write-ahead-log persistence, shard it to cut lock contention, shrink critical sections, find deadlocks by inspection, and explain LRU eviction built from a linked list and a hash map.

  DatabricksSoftware EngineerSystem DesignOnsite
• Solve Grid Path and Graph SamplingMedium

  This question tests the ability to solve a shortest-path problem with multiple constraints using Dijkstra's algorithm, followed by understanding sampling techniques for connected graph structures.

  DatabricksSoftware EngineerCoding & AlgorithmsTechnical Screen
• Solve graph path, interval deletion, and robberyMedium

  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 graph path, interval deletion, and robbery states assumptions, handles edge cases, explains trade-offs, and shows how to validate the result clearly.

  DatabricksSoftware EngineerCoding & AlgorithmsHR Screen
• Test coin fairness from 560 tails in 1000 flipsHard

  This problem evaluates hypothesis testing for proportions—formulating null and alternative hypotheses, applying the binomial-to-normal approximation, and interpreting p-values; it belongs to Statistics & Math for Data Scientist roles and is pitched at an introductory/undergraduate applied statistics level.

  DatabricksData ScientistStatistics & MathTechnical Screen
• Thread-Safe Durable Event Writer Shared by Thousands of ThreadsMedium

  Design a thread-safe DataWriter whose push method durably appends opaque records of up to 1 KB to one local file while thousands of threads call it at once. Tests durability contracts, batching disk syncs across callers, crash-safe record framing and handling of failed writes.

  DatabricksSoftware EngineerSystem DesignOnsite