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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
- Companies
- 11
- Topics
- 8
- Languages
Showing 6811–6840 of 9403 results
- 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 - PerplexityMediumMachine Learning EngineerTrain and improve a scikit-learn binary classifier
This problem tests your proficiency in the scikit-learn workflow, specifically focusing on data preprocessing, addressing class imbalance in imbalanced datasets, and selecting appropriate metrics beyond accuracy.
Machine LearningTechnical Screenscikit-learnImbalanced DataModel Evaluation - 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 - PinduoduoHardSoftware EngineerExplain Employer Interest and Next-Role Priorities
This question tests a candidate's ability to research a company's unique market position and align their personal professional trajectory with the firm's strategic goals.
Behavioral & LeadershipTechnical ScreenBehavioralCareer StrategyCompany Research - PinduoduoHardSoftware EngineerExplain Team Services and Data-Ownership Boundaries
This question tests your ability to articulate the architecture of your past projects, focusing on service boundaries, inter-team dependencies, and ownership models in a complex technical environment.
Behavioral & LeadershipTechnical ScreenSystem DesignCommunicationDistributed Systems - PinduoduoHardSoftware EngineerFind Shortest Square-Sum Path
This problem tests your ability to model a shortest-path graph search problem where states are integers and transitions involve adding perfect squares.
Coding & AlgorithmsTechnical ScreenDynamic ProgrammingBFSNumber Theory - PinduoduoMediumSoftware EngineerGenerate a Matrix in Spiral Order
This problem tests your ability to simulate a specific traversal pattern in a 2D grid and maintain precise boundary pointers to fill the matrix correctly.
Coding & AlgorithmsTechnical ScreenArrayMatrixSimulation - PinduoduoEasySoftware EngineerGenerate a Spiral Matrix
This problem tests your ability to manage matrix traversal coordinates and maintain state (direction and boundaries) while iteratively filling a grid.
Coding & AlgorithmsTechnical ScreenArraysMatricesSimulation - PinduoduoMediumSoftware EngineerLongest Single-Letter Substring After at Most k Character Changes
Given a string of uppercase letters and a budget of at most k single-character changes, find the longest run of one repeated letter that can be produced. Tests reasoning about which substrings can be made uniform, efficient counting, and a near-linear solution for strings of up to 100,000 characters.
Coding & AlgorithmsTechnical Screen - PinduoduoMediumSoftware EngineerNavigate a Senior Engineering HR Interview
Build a consistent narrative for a senior engineering HR interview covering current scope, motivation, role interest, parallel processes, and compensation. Ground seniority in evidence, protect confidential information, and compare opportunities using total compensation and role fit.
Behavioral & LeadershipTechnical Screen - PinduoduoHardSoftware EngineerPresent Evidence for Professional Strengths and Weaknesses
This question assesses the candidate's self-awareness, ability to reflect on professional growth, and capacity to articulate impact through specific, evidence-based storytelling.
Behavioral & LeadershipTechnical ScreenBehavioralSelf-ReflectionSoft Skills - PinduoduoMediumSoftware EngineerTrace Java Static and Instance Field Initialization
This question tests the understanding of Java class loading, static initialization blocks, and the order of operations between class-level and instance-level fields.
Software Engineering FundamentalsTechnical ScreenJavaJVMStatic-Initialization - PinduoduoMediumSoftware EngineerTraverse a Matrix in Spiral Order
Traverse a rectangular matrix in clockwise spiral order using shrinking boundaries. Handle empty, single-row, and single-column inputs without duplicates while achieving linear time and constant auxiliary space beyond the result.
Coding & AlgorithmsTechnical Screen - PinterestHardSoftware EngineerAI-Assisted Coding: Add a Read-Through Cache for a Product GET API in an Existing Repo
In an AI-assisted coding round, add a read-through cache to an existing service so a product GET API calls ProductRepository less often, then explain the approach. It tests understanding a codebase before prompting, cache placement, expiry, invalidation and concurrency, and proving the change works.
Software Engineering FundamentalsOnsite
Perplexity
Pinduoduo
Pinterest