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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.
- 9403
- Questions
- 546
- Companies
- 11
- Topics
- 8
- Languages
Showing 4321–4350 of 5874 results
- PayPalMediumSoftware EngineerMinimize a String Using Allowed Swaps
This question evaluates understanding of graph connectivity and constrained string reordering, along with proficiency in applying efficient data structures and algorithms for handling large inputs.
Coding & AlgorithmsOnsite - PayPalMediumSoftware EngineerSolve common search/parse/graph frequency tasks
This problem tests your ability to perform a binary search on a rotated sorted array and subsequently count occurrences of elements to identify the top-k most frequent items.
Coding & AlgorithmsTechnical ScreenBinary SearchHash TableHeap - PerceptyxMediumSoftware EngineerDemonstrate a Project and Defend Its Design
Tests your ability to present an end-to-end software project you built or led, defend key technical design decisions and trade-offs, and architect a forward-looking feature extension under live questioning.
Software Engineering FundamentalsTechnical ScreenSystem DesignArchitectureProject Walkthrough - PeregrineMediumSoftware EngineerFetch, group, and print paginated activities
This interview question evaluates algorithm design, data structures, correctness, complexity, edge cases, and implementation details in a realistic interview setting. A strong answer for Fetch, group, and print paginated activities states assumptions, handles edge cases, explains trade-offs, and shows how to validate the result clearly.
Coding & AlgorithmsTechnical Screen - PermitflowMediumSoftware EngineerDistinguish Permit Requirement Outcomes
This problem tests your ability to model state transitions based on complex rule sets and implement efficient logic to resolve status precedence when multiple criteria are met.
Coding & AlgorithmsTechnical ScreenAlgorithmsLogicSet Theory - PerplexityMediumSoftware EngineerDesign a CreditTracker with expirations
This question evaluates a candidate's ability to design and implement data structures and algorithms for managing time-bound resources with non-monotonic (out-of-order) operations, emphasizing correctness and efficiency within the coding & algorithms domain.
Coding & AlgorithmsTechnical Screen - PerplexityHardSoftware EngineerDesign a personal finance aggregator
This question evaluates skills in large-scale system design including API and third-party integrations, data ingestion and normalization, transactional consistency and idempotency, security and privacy controls, data modeling for multi-currency financial records, and operational concerns like alerts and budgeting.
System DesignTechnical Screen - PerplexityMediumSoftware EngineerDesign personalized discovery recommendations
This problem evaluates your ability to design a scalable, real-time recommendation system that balances personalization with content discovery in an information-seeking environment.
ML System DesignOnsiteRecommender SystemsML InfrastructureRanking - PerplexityMediumSoftware EngineerDesign trending queries ranking system
This question tests the ability to design a high-throughput, real-time pipeline that identifies and ranks trending search queries, requiring trade-offs between freshness, accuracy, and system latency.
ML System DesignOnsiteSystem DesignReal-time StreamingRanking - PerplexityHardSoftware EngineerDiagnose overloaded Kubernetes cluster
This question evaluates competency in diagnosing and mitigating production overloads in Kubernetes-based microservice architectures, emphasizing observability, autoscaling behavior, resource constraints, and incident-response reasoning.
System DesignTechnical Screen - PerplexityMediumSoftware EngineerImplement Dependency-Aware To-Do List
Design an in-memory task management system that tracks directed dependencies between tasks, prevents cycles, and unblocks dependent tasks upon completion.
Coding & AlgorithmsTechnical ScreenGraphDesignTopological Sort - PerplexityHardSoftware EngineerImplement Task Dependencies and Failure
This question evaluates understanding of graph-based data structures and algorithms for modeling bidirectional task dependencies, status tracking, and efficient cascading failure propagation in an in-memory task manager.
Coding & AlgorithmsTechnical Screen - PerplexityHardSoftware EngineerImplement resilient LLM provider pool
This English-language summary evaluates a candidate's ability to design a resilient, multi-provider LLM client library encompassing provider management, governance (rate limiting and quotas), resilience mechanisms (health checks, timeouts, circuit breakers), routing (cost- and latency-aware load balancing, retries and fallbacks), observability, security, and concurrency. Commonly asked in the ML System Design domain to assess architectural decision-making and trade-off reasoning for availability, cost, latency, and operational robustness, the question targets practical application and architectural-level thinking rather than purely conceptual or low-level implementation details.
ML System DesignTechnical Screen - PerplexityMediumSoftware EngineerImplement time-versioned KV store with restore
This question evaluates a candidate's ability to design and implement a time-versioned key–value store, assessing knowledge of temporal data structures, versioning semantics, time-travel and range queries, deletion semantics, and rollback/restoration.
Coding & AlgorithmsOnline Assessment - PerplexityMediumSoftware EngineerIn-Memory File System: Add cd and Relative Path Support
A multi-part coding exercise that builds an in-memory file system with directories, files and listings over absolute paths, then adds a cd command and relative path support to every operation. It tests tree data structures, path normalization with dot and dot-dot components, consistent error handling and safely refactoring earlier code.
Software Engineering FundamentalsTechnical Screen - PerplexityHardSoftware EngineerIn-Memory File System: Strict mkdir, touch, ls, rm, rmdir and a Command Runner
A two-part coding exercise to build an in-memory file system: first mkdir, touch and ls with strict path validation and no implicit creation of parent directories, then rm, rmdir and a function that executes command sequences. It tests tree modeling, error handling and working against provided tests.
Software Engineering FundamentalsOnsite - PersistenceMediumSoftware EngineerExplain Lazy Loading and Frontend Code Splitting
This question tests your understanding of performance optimization techniques in large-scale frontend applications, specifically how to balance initial load time against runtime latency.
Software Engineering FundamentalsOnsiteFrontendPerformanceArchitecture - PersistenceMediumSoftware EngineerReason About Indexes, Kafka, and Database Locking
Tests practical database indexing, Kafka event ingestion with idempotency guarantees, and row-level locking strategies to prevent concurrency bugs and deadlocks in an inventory and order processing pipeline.
Software Engineering FundamentalsOnsiteDatabasesPostgreSQLKafka - PersonaHardSoftware EngineerImplement a Versioned Key-Value File Store
Practice a Persona coding interview problem focused on implement a versioned key-value file store. The prompt emphasizes edge cases, clean implementation, and verifiable test behavior without revealing the solution.
Coding & AlgorithmsOnline Assessment - PikaHardSoftware EngineerEvaluate Spreadsheet Cells and Reject Circular References
Implement a small spreadsheet whose cells hold integers or single-reference formulas with offsets. Evaluate through current dependencies, propagate updates, report unset chains, and reject a formula atomically whenever it would introduce a circular reference.
Coding & AlgorithmsTechnical Screen - PikaMediumSoftware EngineerImplement text formatter and sum subarray products
This question evaluates algorithmic problem-solving and implementation skills across string formatting (line breaking and space management) and array-based combinatorial computation (sum of subarray products), emphasizing correctness, edge-case handling, and analysis of time and space complexity.
Coding & AlgorithmsOnline Assessment - PilotEasySoftware EngineerExplain Python and Web Basics
This question evaluates foundational competencies in Python language semantics (list vs tuple, identity vs equality) and web fundamentals (HTTP vs HTTPS, CRUD and API concepts), assessing knowledge of data structures, object identity, protocol security, and how CRUD operations map to web services.
Software Engineering FundamentalsTechnical Screen - PilotEasySoftware EngineerSolve Anagram Without Sorting
This question evaluates proficiency in string manipulation, character frequency analysis, and asymptotic time/space complexity reasoning. It is commonly asked in the coding & algorithms domain to test practical application of basic data structures (string processing and frequency-based counting), correctness under input constraints, and the ability to design efficient, linear-time solutions rather than purely conceptual reasoning.
Coding & AlgorithmsTechnical Screen - PinduoduoMediumSoftware EngineerClockwise Spiral Matrix Traversal That Turns at Blocked Cells
Return the values of a matrix in clockwise spiral order starting from the top-left cell, then extend the walk so that blocked cells force clockwise turns and can end it early. Tests precise grid simulation, direction rotation, visited and boundary checks, and an unambiguous stopping rule.
Coding & AlgorithmsTechnical Screen - PinduoduoMediumSoftware EngineerCompute longest increasing subsequence length
This question tests the ability to solve the Longest Increasing Subsequence (LIS) problem, specifically targeting the transition from a standard dynamic programming approach to an optimized binary search solution.
Coding & AlgorithmsTechnical ScreenDynamic ProgrammingBinary SearchArrays - PinduoduoHardSoftware EngineerCount Longest Substrings After Character Replacements
This problem tests the sliding window technique with dynamic constraints, requiring an efficient way to track window state and calculate valid substring counts.
Coding & AlgorithmsTechnical ScreenSliding WindowTwo PointersStrings - PinduoduoMediumSoftware EngineerDescribe toughest project experience
This question evaluates a candidate's leadership, problem-solving, communication, prioritization, and project-management competencies by probing how they handled a high-difficulty project experience.
Behavioral & LeadershipTechnical Screen - PinduoduoMediumSoftware EngineerDesign a Recency-Eviction Cache
This problem tests your ability to implement a Least Recently Used (LRU) cache using a combination of a hash map and a doubly linked list to achieve constant time operations.
Coding & AlgorithmsTechnical ScreenHash MapLinked ListLRU Cache - PinduoduoEasySoftware EngineerDiscuss Your Background, Job-Change Motivation, and Offer Acceptance Factors
This interview assessment evaluates how effectively you articulate your professional trajectory, motivation for changing roles, cultural alignment with high-intensity engineering environments, and pragmatic expectations around compensation and cross-region collaboration.
Behavioral & LeadershipTechnical Screenbehavioralcareer-motivationcultural-fit - PinduoduoMediumSoftware EngineerDiscuss a Difficult Project and Your Next-Role Goals
This question assesses your ability to articulate technical complexity, demonstrate individual ownership during project challenges, and align your personal career trajectory with the goals of a high-growth environment.
Behavioral & LeadershipTechnical ScreenBehavioralLeadershipProject Management
PayPal
Perplexity
Pinduoduo