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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.
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Showing 2761–2790 of 9403 results
- DatabricksHardSoftware EngineerImplement a Tic-Tac-Toe game API
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.
Coding & AlgorithmsOnsiteAlgorithmsData StructuresOptimization - DatabricksMediumSoftware EngineerImplement a rate-limited hit counter
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.
Coding & AlgorithmsOnsite - DatabricksMediumSoftware EngineerImplement a sliding-window hit counter
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.
Coding & AlgorithmsTechnical Screen - DatabricksMediumSoftware EngineerImplement a snapshotable set with iterators
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.
Coding & AlgorithmsOnsite - DatabricksHardSoftware EngineerImplement an Alternating Tic-Tac-Toe Game
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.
Coding & AlgorithmsTechnical ScreenState ManagementArraysGame Theory - DatabricksMediumSoftware EngineerImplement lazy array and KV store
This problem tests your ability to implement lazy computation using function composition and design a stateful data structure with metadata tracking.
Coding & AlgorithmsOnsiteFunctional ProgrammingData StructuresAPI Design - DatabricksMediumSoftware EngineerImplement run-length encoding and decoding
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.
Coding & AlgorithmsOnsite - DatabricksHardSoftware EngineerImplement streaming RLE and bit-packed codec
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.
Coding & AlgorithmsOnsite - DatabricksMediumSoftware EngineerInteger Set with O(1) Snapshot Iterators Unaffected by Later Changes
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.
Software Engineering FundamentalsOnsite - DatabricksMediumSoftware EngineerLowest-Price Book Aggregator Fanning Out to Hundreds of Async Bookstores
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.
System DesignOnsite - DatabricksMediumSoftware EngineerOptimal Commute: Nearest Transit Distance in a City Grid
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.
Coding & AlgorithmsTechnical ScreenBreadth-First SearchMatrixGraph - DatabricksHardSoftware EngineerOptimize a SQL query plan tree
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.
Coding & AlgorithmsTechnical ScreenTreesRecursionDatabase Internals - DatabricksMediumSoftware EngineerPartition a Target String by Source Substrings
Determine the minimum number of contiguous substrings from a source string required to reconstruct a target string.
Coding & AlgorithmsOnsitestringsgreedysuffix-automaton - DatabricksMediumSoftware EngineerPath Between Two Preorder-Numbered Nodes of an Implicit Fibonacci Tree
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.
Coding & AlgorithmsOnsite - DatabricksHardSoftware EngineerPresent a Technical Project Under Active Follow-Up
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.
Behavioral & LeadershipOnsiteSystem DesignLeadershipTechnical Communication - DatabricksMediumSoftware EngineerReferral Credit Tracker with Indirect Referrals
Build a referral credit tracker with account creation, threshold queries, deterministic ordering, and correct credit propagation through indirect referrals.
Coding & AlgorithmsOnsite - DatabricksEasyData ScientistRelate coefficients under linear feature transformation
This question tests the relationship between regression coefficients when predictors undergo linear transformations, specifically focusing on scaling and centering transformations.
Statistics & MathTechnical ScreenLinear RegressionLinear AlgebraFeature Engineering - DatabricksMediumSoftware EngineerReport the Winner After Every Move on an n x n Tic-Tac-Toe Board
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.
Coding & AlgorithmsOnsite - DatabricksMediumMachine Learning EngineerRetrieve and Rerank Tables and Notebooks for a Data-Aware Coding Agent
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.
ML System DesignOnsite - DatabricksMediumSoftware EngineerShare background, conflicts, and proud project details
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.
Behavioral & LeadershipHR Screen - DatabricksMediumSoftware EngineerSingle-Machine Cache with WAL Persistence, Sharded Locks and LRU
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.
System DesignOnsite - DatabricksMediumSoftware EngineerSolve Grid Path and Graph Sampling
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.
Coding & AlgorithmsTechnical ScreenDijkstraGraph AlgorithmsDynamic Programming - DatabricksMediumSoftware EngineerSolve graph path, interval deletion, and robbery
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.
Coding & AlgorithmsHR Screen - DatabricksHardData ScientistTest coin fairness from 560 tails in 1000 flips
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.
Statistics & MathTechnical Screen - DatabricksMediumSoftware EngineerThread-Safe Durable Event Writer Shared by Thousands of Threads
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.
System DesignOnsite - DatabricksMediumSoftware EngineerTic-Tac-Toe Against a Deterministic Automatic Opponent
Build an automated Tic-Tac-Toe opponent with perfect-play minimax, deterministic move ties, board events, invalid attempts, and terminal-state handling.
Coding & AlgorithmsOnsite - DatabricksMediumSoftware EngineerTic-Tac-Toe with Automatic Turns and Board Snapshots
Implement two-player Tic-Tac-Toe with automatic turn changes, board snapshots, rejected moves, winning lines, and full-board draws.
Coding & AlgorithmsOnsite - DatadogMediumSoftware EngineerBuild span trees from unordered trace spans
This problem tests your ability to reconstruct a parent-child hierarchical tree from an unordered collection of trace spans by leveraging parent ID references and sorting mechanisms.
Coding & AlgorithmsTechnical ScreenTreesHash MapsSorting - DatadogMediumSoftware EngineerCompute sliding window sums by tag
This question evaluates understanding of sequence processing, sliding-window aggregation, filtering by tag, and efficient state management in tagged time-series or event data, testing algorithmic efficiency and correctness.
Coding & AlgorithmsOnsite - DatadogMediumSoftware EngineerDeep-dive a recent project
This question evaluates project ownership, technical leadership, system architecture, trade-off reasoning, and the ability to articulate goals, constraints, decisions, metrics and postmortem lessons in a software engineering context.
Behavioral & LeadershipTechnical Screen
Databricks
Datadog