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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
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- 11
- Topics
- 8
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Showing 1051–1080 of 3640 results
- 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 - 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 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 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 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 - DatadogEasySoftware EngineerEngineering Manager Interview: Your Technical Contribution and an Annoying Teammate
A hiring manager conversation for an engineering manager role: introduce yourself, explain your own technical contribution to a project you led, and describe a time a team member annoyed you. It tests whether a manager can separate personal technical judgment from team output and handle interpersonal friction with candor.
Behavioral & LeadershipOnsite - DatadogHardSoftware EngineerImplement Prefix Match Filter
This question evaluates understanding of prefix-based string matching, data structure design (hash-based sets and trie/prefix tree), and algorithmic competencies including efficient in-memory storage and deduplication of matches.
Coding & AlgorithmsOnsite - DatadogMediumSoftware EngineerImplement a Snowflake Query Client
This question evaluates API client design, asynchronous query lifecycle management, result retrieval, robust error handling, and secure credential handling for a cloud data warehouse.
Coding & AlgorithmsOnsite - DaveEasyMachine Learning EngineerOwn and Resolve a Bug in Production
This question tests your ability to structure a high-stakes professional failure using the STAR method, focusing on technical accountability and systemic improvement.
Behavioral & LeadershipOnsiteBehavioralLeadershipProduction-Support - DaveEasyMachine Learning EngineerParse JSON Accounts into Typed Python Objects and Prepare Features
This problem tests your ability to sanitize and transform raw JSON account data into a structured format while enforcing strict numerical integrity and data consistency.
Data Manipulation (SQL/Python)OnsitePythonData CleaningJSON - DecagonMediumSoftware EngineerDesign a Single-Domain Chatbot
This question evaluates a candidate's ability to design production-grade conversational AI systems, testing competencies in retrieval-augmented generation, document ingestion and indexing, multi-turn session management, prompt construction, model serving, grounding and citation, safety, access control, monitoring, and operational trade-offs.
ML System DesignOnsite - DecagonMediumSoftware EngineerDesign the Security Architecture for an LLM Chatbot Product
A system design question on securing a chatbot built on a large language model that talks with people outside the company. It tests threat modeling for prompt injection and data leakage, user authentication and tool authorization outside the model, tenant isolation, sensitive-data handling, abuse controls, auditing and incident response.
System DesignOnsite - DecagonMediumSoftware EngineerEnumerate 4x4 Tic-Tac-Toe Games
This question evaluates understanding of recursion and backtracking, exhaustive game-tree enumeration, and state representation for combinatorial game analysis.
Coding & AlgorithmsOnsite - DecagonMediumSoftware EngineerImplement CSAT tracking and call timing
This problem tests your ability to manage stateful data during event processing and calculate exclusive execution times from a stream of nested function logs.
Coding & AlgorithmsOnsiteStackSimulationData Structures - DecagonMediumSoftware EngineerShopping Cart with Undo and Redo for Add and Remove Operations
A coding exercise to build a shopping cart class whose add and remove operations can be undone and redone. It tests how history entries are represented, how capped removals and deleted lines are reversed exactly, what a new change does to the redo history, and how empty-history cases are handled.
Software Engineering FundamentalsOnsite - DecagonMediumSoftware EngineerWalk Through a Project, a Project That Went Wrong, and How You Use AI
A culture-focused behavioral interview with three questions: describe a project you worked on, describe a project that went wrong, and explain how you use AI tools in your work. It tests clear ownership of decisions, honest reflection on failure, and practical judgment about verifying AI output and respecting its limits.
Behavioral & LeadershipOnsite - Deutsche BankHardSoftware EngineerAnswer mixed behavioral and technical deep-dive questions
This question evaluates a software engineer's combined behavioral and technical competencies, including communication, leadership, conflict resolution, system integration and API contracts, debugging, testing strategies, documentation practices, and use of AI tools.
Behavioral & LeadershipOnsite - Deutsche BankHardSoftware EngineerExplain Java follow-ups after solving coding problem
This question evaluates proficiency in Java programming and software engineering fundamentals, covering competencies such as refactoring for changing requirements, input validation, performance analysis for large datasets, selection of Java collections, generics, exception design, and unit testing.
Software Engineering FundamentalsOnsite - Deutsche BankHardSoftware EngineerSolve tree equality and valid parentheses
This problem set evaluates core skills in data structures and algorithmic reasoning, specifically binary tree structural equality and bracket-matching for strings, testing understanding of tree traversal, recursion, and stack-based parsing.
Coding & AlgorithmsOnsite - DigitaloceanMediumSoftware EngineerClarify a Longest-Repeating-Character Replacement Problem
Clarify replacement and substring semantics, then analyze the conditional sliding-window criterion based on window size and maximum character frequency.
Software Engineering FundamentalsOnsite - DigitaloceanMediumSoftware EngineerDesign a Multi-Organization Advertising Platform with Performance Statistics
Design ad management, serving, event collection, deduplicated statistics, and fair performance comparisons across organizations and campaigns.
System DesignOnsite - DigitaloceanMediumSoftware EngineerSpecify House-Selection Constraints Before Choosing a Robbery Dynamic Program
Clarify house layout and selection conflicts, derive a conditional linear dynamic program, and explain how circular or graph constraints change it.
Software Engineering FundamentalsOnsite - DiscordMediumSoftware EngineerDemonstrate effective AI-assisted coding workflow
This question evaluates a candidate's proficiency with AI-assisted coding workflows, including prompt formulation, tool and library selection, design critique, testing approaches, and iterative feature development to demonstrate engineering judgment and ownership.
Software Engineering FundamentalsOnsite - DiscordEasySoftware EngineerDesign Slack-like chat system
An onsite system-design interview question asking you to design the chat subsystem for a Slack/Discord-like app: workspaces, channels, 1:1 and group DMs, full message history, real-time updates, and edit/delete. It tests data modeling, storage and partitioning, fanout strategy, real-time WebSocket delivery, and per-conversation ordering and consistency.
System DesignOnsite - DiscordHardData EngineerDesign Video Call Analytics Tables
This question evaluates data modeling and analytics competencies including event schema design, dimensional modeling (facts and dimensions), ETL/cleaning and deduplication, and time-windowed SQL aggregation.
System DesignOnsite - DiscordMediumSoftware EngineerDesign a TCP Discord-like chat server
This question evaluates a candidate's skills in system design, TCP-based protocol design, real-time messaging, data modeling, persistence, session/reconnection handling, and concurrency control for backend services.
System DesignOnsite - DiscordMediumSoftware EngineerDesign leader election using Redis leases
This question evaluates a candidate's understanding of distributed coordination and leader election using a central in-memory datastore, focusing on lease-based leadership, failover, and correctness under partitions and clock skew.
System DesignOnsite
Databricks
Datadog
Decagon
Discord