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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
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- 11
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Showing 1711–1740 of 4616 results
- GoogleMediumSoftware EngineerDesign a rolling hit counter API
This question tests the ability to design an efficient data structure for time-series aggregation using a sliding window approach with O(1) time complexity per operation.
Coding & AlgorithmsTechnical ScreenData StructuresConcurrencyDesign - GoogleMediumData ScientistDesign a scalable video platform database
This question evaluates relational database design and data engineering competencies—including schema modeling, many-to-many relationships, idempotent ingest, indexing and partitioning, OLTP versus analytics integration, GDPR-compliant deletion strategies, and query formulation—within the Data Manipulation (SQL/Python) domain for a Data Scientist role. It is commonly asked to assess both conceptual understanding and practical application of scalable data architectures, performance tuning, and compliance trade-offs, focusing on the ability to reason about schema choices, read/write optimization, and analytics integration without implementation details.
Data Manipulation (SQL/Python)Technical Screen - GoogleMediumSoftware EngineerDesign a waitlist system with top/bottom K
This problem tests your ability to design a dynamic waitlist using efficient data structures to support logarithmic time complexity for insertions, deletions, and ranking operations.
Software Engineering FundamentalsTechnical ScreenData StructuresDesignComplexity Analysis - GoogleMediumSoftware EngineerDesign an Agent for Internal Document Search
Design an enterprise search agent that provides grounded, cited answers over internal knowledge repositories while strictly enforcing access control lists (ACLs) and handling prompt injection.
ML System DesignTechnical ScreenRAGSearch SystemsLLM Agents - GoogleMediumSoftware EngineerDesign an LLM Agent for Manufacturing: Production Status, Work Orders and Quotes
Design an LLM-powered agent for a manufacturing business that checks production progress, opens work orders and gives customers price quotes. Probes tool design for reads and writes, how to stop the agent from inventing statuses or prices, and how to enforce user permissions outside the model.
ML System DesignTechnical Screen - GoogleHardData ScientistDesign an Unbiased Upgrade Experiment
This question tests the ability to design an A/B test for a software upgrade, specifically focusing on handling non-compliance, selection bias, and the identification of causal effects in a real-world product environment.
Analytics & ExperimentationTechnical ScreenCausal InferenceExperiment DesignA/B Testing - GoogleHardSoftware EngineerDesign anomaly detection and response platform
This question evaluates a candidate's competency in designing end-to-end ML-driven systems that handle large-scale, low-latency OS snapshot ingestion, binary anomaly detection, decisioning and action orchestration with multi-tenant security, auditability, and failure rollback.
ML System DesignTechnical Screen - GoogleMediumSoftware EngineerDesign at-least-once notification delivery
This question evaluates expertise in reliable distributed systems design, including at-least-once delivery semantics, idempotency and deduplication strategies, retry and dead-letter handling, API and message-schema design, ordering and out-of-order handling, and scalability for high-throughput multi-tenant notification platforms.
System DesignTechnical Screen - GoogleHardSoftware EngineerDesign deduplicated file storage on filesystem
This question evaluates system design and storage engineering competencies, including multi-tenant isolation, authentication and authorization models, content-addressable storage and deduplication, reference counting and garbage collection, concurrency control, API surface design, and scaling across nodes using only filesystem primitives.
System DesignTechnical Screen - GoogleHardSoftware EngineerDesign distributed log storage service
This question evaluates a candidate's expertise in designing distributed storage systems, covering partitioned append-only logs, high-throughput writes and reads, replication, retention, indexing, compaction, leader/follower roles, and recovery mechanisms.
System DesignTechnical Screen - GoogleHardSoftware EngineerDesign distributed transactions protocol
This question evaluates a candidate's understanding of distributed transactions, coordination protocols, fault tolerance, consistency, and reliability across microservices and databases.
System DesignTechnical Screen - GoogleHardSoftware EngineerDesign executable notebook service APIs
This question evaluates a candidate's competence in designing secure, scalable systems for executing user-supplied code, covering API design, sandboxing and isolation, dependency management, resource limits, scheduling, and streaming proxies for logs/results.
System DesignTechnical Screen - GoogleHardSoftware EngineerDesign high-throughput event subscription system
This question evaluates a candidate's ability to design scalable, fault-tolerant event ingestion and subscription architectures, covering distributed systems, high-throughput messaging, content-based filtering, multi-tenant isolation, API/webhook design, delivery semantics, backpressure, sharding, security, and operational observability.
System DesignTechnical Screen - GoogleHardSoftware EngineerDesign key management service
This question evaluates system design and security competencies—specifically cryptographic key lifecycle management, HSM integration, access control, auditing, multi-tenant isolation, and scalability—within the System Design domain.
System DesignTechnical Screen - GoogleHardMachine Learning EngineerDesign multi-GPU matrix multiplication
This question evaluates proficiency in multi-GPU parallelism and system-level ML engineering, covering data partitioning, inter-GPU communication primitives, compute scheduling and overlap, memory layout and buffer reuse, numerical precision trade-offs, synchronization, scalability, and failure handling.
ML System DesignTechnical Screen - GoogleMediumSoftware EngineerDesign nearest-available-taxi lookup with updates
This question assesses the ability to design a high-concurrency geospatial system that maintains real-time state for moving entities and supports low-latency queries.
System DesignTechnical ScreenGeospatialScalabilityCaching - GoogleHardSoftware EngineerDesign quota enforcement for high concurrency
This question evaluates a candidate's understanding of distributed system design and engineering competencies related to quota enforcement, high-throughput rate limiting, consistency models, sharding, and concurrency control under very high QPS.
System DesignTechnical Screen - GoogleHardSoftware EngineerDesign relational-to-NoSQL migration pipeline
This question evaluates a candidate's competency in designing a relational-to-NoSQL migration pipeline, covering distributed systems and data engineering concepts such as consistent snapshotting, change-data-capture, per-key ordering, idempotency, exactly-once behavior, schema evolution, partitioning, and operational reliability.
System DesignTechnical Screen - GoogleMediumSoftware EngineerDesign server allocation for multi-type nodes
This question evaluates understanding of scalable resource-allocation and matching systems, encompassing data-structure and index design, availability tracking, fragmentation minimization, concurrency control, and failure handling for large node pools.
Coding & AlgorithmsTechnical Screen - GoogleMediumSoftware EngineerDesign set with O(1) random access
This question evaluates skill in designing a composite data structure that supports average O(1) insertion, deletion, and uniform random access, and tests understanding of hashing, indexing, randomness, and concurrency control.
Coding & AlgorithmsTechnical Screen - GoogleHardSoftware EngineerDesign street-view image ingestion and storage system
This question tests the ability to design a high-throughput, fault-tolerant ingestion pipeline for massive geospatial media, focusing on distributed storage strategies, data integrity, and efficient retrieval at scale.
System DesignTechnical ScreenScalabilitySpatial IndexingData Ingestion - GoogleHardSoftware EngineerDesign viewing history and resume service
This question evaluates a candidate's ability in large-scale system design, covering distributed state management, API design, data modeling for per-user progress, idempotent update semantics, cross-device synchronization, and privacy/compliance considerations.
System DesignTechnical Screen - GoogleHardMachine Learning EngineerDetect and Prevent Reward Hacking
Assess the candidate's understanding of reward hacking (specification gaming) in reinforcement learning from human feedback (RLHF), focusing on diagnosing exploitation patterns, designing detection metrics, applying conservative policy updates, and implementing recovery safeguards.
Machine LearningTechnical ScreenRLHFReward ModelingLLM Alignment - GoogleMediumData ScientistDetermine Impact of New Chat-Notification on User Engagement
Determine Impact of New Chat-Notification on User Engagement evaluates statistical assumptions, formulas, estimation strategy, uncertainty, edge cases, and interpretation in a realistic interview setting. A strong answer states assumptions, handles edge cases, explains trade-offs, and shows how to validate the result clearly.
Statistics & MathTechnical Screen - GoogleEasyData ScientistDetermine Normality of Single Observation with Z-Test
Evaluates hypothesis testing for a single observation against a fully specified standard normal distribution. Strong answers state hypotheses, use z = x, define critical values and p-values, and note limitations.
Statistics & MathTechnical Screen - GoogleMediumSoftware EngineerDetermine Reporting Relationships
This question evaluates understanding of hierarchical relationship modeling, transitive inference across relations, and dynamic data-structure design for tracking manager and peer links.
Coding & AlgorithmsTechnical Screen - GoogleMediumSoftware EngineerDetermine whether two nodes are related
This problem tests your ability to determine connectivity between two nodes in a directed graph, specifically modeling ancestry relationships.
Coding & AlgorithmsTechnical ScreenGraphsDFSBFS - GoogleHardSoftware EngineerDetermine winner in stack-merging game
This problem tests your ability to model a combinatorial game using the Sprague-Grundy theorem and memoization to determine the winner of a state-dependent stack-merging process.
Coding & AlgorithmsTechnical ScreenGame TheoryRecursionMemoization - GoogleHardData ScientistDiagnose Google Meet Disconnections and Assess Business Impact
Evaluates reliability analytics for Google Meet disconnections and enterprise renewal impact. Strong answers define call drops, use client and server logs to localize root causes, estimate account-level retention impact, and prioritize fixes using quantified business risk.
Analytics & ExperimentationTechnical Screen - GoogleHardData ScientistDiagnose and fix flawed model fit
This question tests your ability to diagnose poor model performance in a binary classification task involving imbalanced data, high-cardinality categorical features, and potential bias.
Machine LearningTechnical ScreenClassificationImbalanced DataFeature Engineering
Google