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Software Engineer 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 4921–4950 of 5874 results
- SigmacomputingEasySoftware EngineerImplement a basic pivot table with totals
This question evaluates a candidate's ability to perform in-memory data aggregation, multi-dimensional grouping, handling missing combinations, and formatted text output for pivot tables including row/column totals.
Coding & AlgorithmsTechnical Screen - SnapchatMediumSoftware EngineerCheck if a binary tree is complete
This problem tests your understanding of binary tree properties and your ability to perform a level-order traversal to verify structural completeness.
Coding & AlgorithmsTechnical ScreenBinary TreeBFSData Structures - SnapchatHardSoftware EngineerCompare WebSocket, SSE, and long polling
This question tests a software engineer's depth in web networking fundamentals, covering real-time communication protocols and the OSI and TCP/IP models. It assesses practical knowledge of WebSocket, SSE, and long polling trade-offs, as well as understanding of how modern transport protocols like QUIC differ from TCP in multiplexing, handshake latency, and connection migration.
Software Engineering FundamentalsOnsite - SnapchatMediumSoftware EngineerCompute islands in a binary grid
This question evaluates a candidate's competency in modeling grids as graphs, detecting connected components, applying graph traversal algorithms (DFS/BFS) and disjoint-set (Union-Find) data structures, and analyzing algorithmic time and space complexity.
Coding & AlgorithmsOnsite - SnapchatHardSoftware EngineerCompute longest increasing path in matrix
This question evaluates algorithmic problem-solving skills in graph traversal and dynamic programming on matrices, measuring understanding of state representation and performance trade-offs in grid-based searches within the Coding & Algorithms domain.
Coding & AlgorithmsOnsite - SnapchatHardSoftware EngineerCompute shortest path in a 2D grid
This question evaluates understanding of graph traversal and pathfinding concepts, including modeling a 2D grid as a graph and reasoning about shortest-path computations and obstacle handling.
Coding & AlgorithmsOnsite - SnapchatMediumSoftware EngineerCompute shortest recursive string encoding
This question evaluates proficiency in string manipulation, pattern detection, recursion, and dynamic programming for efficient sequence compression in the Coding & Algorithms domain.
Coding & AlgorithmsOnline Assessment - SnapchatMediumSoftware EngineerCompute sliding window median
This question evaluates the ability to maintain a running median over a sliding window, testing competencies in data structures, order statistics, dynamic updates, and algorithmic efficiency within the Coding & Algorithms domain.
Coding & AlgorithmsTechnical Screen - SnapchatMediumSoftware EngineerCount Grid Islands That Never Touch the Border
Coding problem on a binary grid where 0 marks land and 1 marks water: count the islands, connected horizontally or vertically, that have no cell on the grid's border. It tests grid traversal, connected components and careful handling of islands that reach the edge through a single cell.
Coding & AlgorithmsOnsite - SnapchatMediumSoftware EngineerCount islands with eight-direction adjacency
This question evaluates a candidate's competency in graph traversal algorithms and data-structure trade-offs by counting connected components on a grid with eight-direction adjacency, focusing on BFS/DFS behavior and optional Union-Find approaches.
Coding & AlgorithmsTechnical Screen - SnapchatHardSoftware EngineerCount ways to decode digit string
This question evaluates a candidate's skill in dynamic programming and combinatorial reasoning about string partitioning, testing competency in counting valid decodings under constraint handling and edge-case analysis.
Coding & AlgorithmsOnsite - SnapchatMediumSoftware EngineerDesign a Column-Queryable KV Database
This problem tests your ability to design a distributed key-value storage system that supports efficient column-based filtering and range scans, balancing write performance against analytical query capabilities.
System DesignOnsiteDistributed SystemsNoSQLStorage - SnapchatMediumSoftware EngineerDesign a Metrics System
Design a high-throughput, low-latency metrics collection, aggregation, and querying platform. The question tests your ability to handle multi-dimensional time-series data, mitigate high-cardinality label explosions, and design tiered storage for varying query windows.
System DesignOnsiteTime SeriesDistributed SystemsScalability - SnapchatHardSoftware EngineerDesign a News Aggregator
This question evaluates a candidate's ability to design scalable content ingestion and distribution systems, encompassing API-driven fetching, scheduling, deduplication, storage, ranking, freshness guarantees, API rate limiting, and efficient article serving.
System DesignOnsite - SnapchatMediumSoftware EngineerDesign a Pre-Login Risk and Challenge Service
Design a low-latency, resilient pre-login security service that evaluates risk signals, issues dynamic verification challenges, and verifies responses without exposing authentication flows to replay attacks.
System DesignOnsiteSecurityDistributed SystemsAuthentication - SnapchatMediumSoftware EngineerDesign a device owner lookup service
This question tests the ability to design a distributed system for tracking the mapping between ephemeral devices and their currently signed-in users, focusing on handling event concurrency and high-throughput read/write operations.
System DesignOnsiteDistributed SystemsConcurrencyCaching - SnapchatMediumSoftware EngineerDesign a metrics collection and alerting system
This question evaluates system design competencies such as scalable time-series data modeling, ingestion and storage architecture, query latency versus retention trade-offs, and alert evaluation logic within the System Design domain.
System DesignOnsite - SnapchatHardSoftware EngineerDesign a streaming ads system
This question evaluates a candidate's competency in designing low-latency, scalable, and privacy-compliant ad-insertion platforms, encompassing distributed systems, real-time bidding integration, ad format and measurement standards, content and identity signal processing, pacing/frequency control, and multi-region fault tolerance.
System DesignOnsite - SnapchatMediumSoftware EngineerDesign a swipeable video feed backend
This question evaluates system-design competence for building scalable, low-latency backend services that handle feed vending, pagination, personalized ranking, caching, storage, and content eligibility; it is categorized under System Design and tests practical application of distributed systems and backend data engineering principles.
System DesignOnsite - SnapchatMediumSoftware EngineerDesign and Implement a Thread-Safe LRU Cache
Design an `O(1)` LRU cache and extend it with clear thread-safety semantics. The solution covers hash-map and doubly linked-list invariants, boundary cases, linearization points, single-lock correctness, sharding trade-offs, eviction callbacks, and concurrent testing.
Software Engineering FundamentalsTechnical Screen - SnapchatHardSoftware EngineerDesign product co-occurrence analytics API
This question evaluates design skills for RESTful APIs and backend systems, covering API schema and versioning, authentication and rate limiting, caching and cache invalidation, storage models, precomputation pipelines, consistency and staleness bounds, monitoring, and operational concerns.
System DesignOnsite - SnapchatMediumSoftware EngineerDesign real-time ad impression and spend tracking
This question tests the ability to design a high-throughput, fault-tolerant system capable of tracking massive volumes of ad impression events and calculating real-time budget spending.
System DesignOnsiteDistributed SystemsCachingHigh Throughput - SnapchatHardSoftware EngineerDesign ride-hailing and price alert systems
This question evaluates a candidate's competency in large-scale system design, including distributed architecture, real-time data processing, geo-spatial indexing and low-latency matching for ride-hailing, plus scalable ingestion, time-series storage, rule evaluation, and reliable notification pipelines for price-tracking, within the System Design domain. It is commonly asked to assess architectural trade-offs around scalability, consistency, availability, fault tolerance and operational concerns, testing practical application of architectural patterns alongside conceptual understanding of data modeling and real-time constraints.
System DesignOnsite - SnapchatHardSoftware EngineerDesign short URL service with click counting
This question tests the ability to design a distributed URL shortening service, focusing on system architecture, database partitioning, and strategies for high-frequency write operations like click tracking.
System DesignTechnical ScreenScalabilityDatabaseCaching - SnapchatMediumSoftware EngineerDetermine blockage and parse HTML tokens
This question evaluates computational geometry and graph connectivity for the circular-stones subproblem and parsing plus tree data-structure manipulation for the HTML-like token subproblem, measuring skills in modeling spatial overlap, graph traversal/union operations, hierarchical DOM construction, and dynamic node insertion/deletion.
Coding & AlgorithmsOnsite - SnapchatMediumSoftware EngineerEngineering Manager Behavioral: Motivation, Taking Feedback and Leading a Reorganization
A Snapchat engineering manager behavioral question in three parts: what motivates you in this role, how you take critical feedback, and how you led a team through a restructuring. It tests self-awareness, growth from feedback, transparent communication and care for people during change.
Behavioral & LeadershipOnsite - SnapchatMediumSoftware EngineerEngineering Manager Scenarios: Promotion Cases, Team Conflict and Performance Plans
A Snapchat engineering manager leadership question covering three people-management scenarios: building a case to promote an engineer, resolving conflict on your team, and managing underperformance through a performance improvement plan. It tests fairness, judgment and coaching.
Behavioral & LeadershipOnsite - SnapchatMediumSoftware EngineerExplain median vs mean for L1/L2
This question evaluates understanding of central tendency and loss functions—specifically the roles of median and mean under L1 (absolute) and L2 (squared) norms—and the geometric extension of these concepts to two-dimensional data.
Statistics & MathTechnical Screen - SnapchatMediumSoftware EngineerFind Duplicate Files with a Hand-Written Directory Traversal
This problem tests iterative directory traversal techniques, efficient file hashing strategies to handle large data, and the ability to manage edge cases like file system inconsistencies or symbolic links.
Software Engineering FundamentalsTechnical ScreenFile SystemHashingIteration - SnapchatMediumSoftware EngineerFind Maximum Island Perimeter
This problem tests grid traversal techniques (DFS/BFS) and the ability to calculate boundary contributions within a connected component in a 2D matrix.
Coding & AlgorithmsTechnical ScreenDFSBFSGrid
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