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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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- 11
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Showing 2011–2040 of 2336 results
- SigmacomputingMediumSoftware EngineerEvaluate a Formula AST with Variables
This problem tests tree traversal techniques, recursive evaluation, and the implementation of short-circuit logic in expression trees containing variables.
Coding & AlgorithmsOnsiteTreesRecursionAST - 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 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 - 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 - 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 - 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 EngineerFind top co-purchased products
This question evaluates algorithmic problem-solving and data engineering skills, focusing on computing and ranking co-occurrence frequencies, choosing efficient data structures for pairwise counts, and contrasting offline batch implementation with streaming updates.
Coding & AlgorithmsOnsite - SnapchatHardSoftware EngineerImplement LRU cache and prime products array
This question evaluates proficiency in implementing efficient mutable data structures and in enumerating combinatorial results, specifically testing understanding of LRU cache eviction behavior and generation of all non-empty subset products from a set of primes.
Coding & AlgorithmsOnsite - SnapchatHardSoftware EngineerImplement a Leaky Bucket Limiter
This problem tests your ability to implement a thread-safe rate limiter using the Leaky Bucket algorithm, requiring careful management of timestamps and shared state.
Coding & AlgorithmsOnsiteConcurrencyRate-LimitingAlgorithms - SnapchatHardSoftware EngineerImplement a size-bounded LRU cache
This problem tests your ability to extend the standard LRU cache pattern to support items with heterogeneous 'weights', requiring a data structure that maintains access order while managing a cumulative capacity constraint.
Coding & AlgorithmsOnsiteLRUHash MapDoubly Linked List - SnapchatHardSoftware EngineerImplement an iOS scrollable grid with navigation
This question tests the ability to build a responsive, performance-optimized grid interface in iOS using modern frameworks like SwiftUI, focusing on layout constraints, state management, and navigation flow.
Software Engineering FundamentalsOnsiteiOSSwiftUILayout - SnapchatMediumSoftware EngineerImplement binary search for boundary index
This question evaluates a candidate's ability to implement binary search for boundary indices, including correct handling of duplicates, providing iterative and recursive variants, and reasoning about time and space complexity.
Coding & AlgorithmsOnsite - SnapchatMediumSoftware EngineerMaximize correct guesses in a hat line puzzle
This problem tests your ability to devise a deterministic strategy for a group of people to maximize correct guesses about their own attributes based on observed information from others.
Coding & AlgorithmsOnsiteLogicParityGreedy Strategy - SnapchatMediumSoftware EngineerRadar Overlaps and Undetected Crossing of a Rectangular Room
Two-part geometry coding problem about circular radars placed inside a rectangular room. For each radar, list every other radar whose coverage overlaps it, then decide whether a point object can travel from the left wall to the right wall without entering any radar's coverage.
Coding & AlgorithmsOnsite - SnapchatHardSoftware EngineerSolve Three Algorithmic Tasks
This set of three problems evaluates competencies in algorithm design and data structures, specifically efficient range counting on timestamped events, constrained selection/matching from double-sided cards, and merging multiple sorted lists.
Coding & AlgorithmsOnsite
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