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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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- 546
- Companies
- 11
- Topics
- 8
- Languages
Showing 6121–6150 of 9403 results
- OpenAIHardMachine Learning EngineerAnalyze matrix multiplication complexity
This question evaluates understanding of time and space complexity for matrix multiplication and memory accounting in ML workloads, testing competency in asymptotic analysis, linear algebra operations, and resource estimation.
Software Engineering FundamentalsTechnical Screen - OpenAIHardData ScientistAssess free-month promotion impact
This question tests your ability to design a rigorous experimentation framework to measure the causal impact of a promotional offer while accounting for self-selection bias and long-term churn behavior.
Analytics & ExperimentationTechnical ScreenA/B TestingCausal InferenceProduct Analytics - OpenAIMediumSoftware EngineerAt-Least-Once Job Queue with Timeouts, Retries, a Dead-Letter Queue and Dependencies
Implement an in-memory job queue with enqueue, reserve, pass, fail and a dead-letter queue, where reservations that outlive their timeout are redelivered for at-least-once delivery, then extend enqueue with job dependencies. It tests state-machine design, timeout tracking, retry accounting and dependency handling.
Software Engineering FundamentalsTechnical Screen - OpenAIMediumSoftware EngineerBehavioral: why OpenAI, AI safety views, 0-to-1 work, feedback, defining success
Behavioral questions reported from OpenAI's software engineering loop: why OpenAI, how you think about AGI and AI safety, a 0-to-1 project, negative feedback you received, and how you defined success for a project. A slide-based project deep dive then probes technical depth under repeated challenge, testing ownership, calibrated judgment and composure.
Behavioral & LeadershipOnsite - OpenAIMediumAndroid EngineerBuild a Compose Rating Card
Tests proficiency in modern Android development with Kotlin and Jetpack Compose, focusing on unidirectional data flow (UDF), custom stateless composables, ViewModel state management, and asynchronous submission handling.
Coding & AlgorithmsTechnical Screenandroidjetpack-composekotlin - OpenAIHardSoftware EngineerBuild a Reliable Streaming Chat UI
This question evaluates understanding of real-time front-end architecture and state management in React, focusing on transient streaming state, concurrency control, UI consistency during tokenized updates, and the appropriate use of hooks such as useRef versus useState in the Software Engineering Fundamentals domain.
Software Engineering FundamentalsHR Screen - OpenAIMediumSoftware EngineerBuild a SaaS API-Credit Ledger With Expiring Grants and Late Events
Implement an API-credit ledger that grants, spends, and reports balances, where each grant expires and spending always draws from the soonest-expiring usable grant first, even when operations arrive out of timestamp order.
Software Engineering FundamentalsOnsitedata-structuresheapevent-ordering - OpenAIMediumFrontend EngineerBuild a Streaming Chat Input
This question evaluates frontend engineering skills including streaming data handling, incremental token-by-token rendering, asynchronous state management, and preserving UI responsiveness during long-running API streams.
Coding & AlgorithmsTechnical Screen - OpenAIHardMachine Learning EngineerBuild and troubleshoot image classification and backprop
Build and troubleshoot image classification and backprop evaluates core ML concepts, assumptions, math intuition, training/evaluation trade-offs, and practical failure modes in a realistic interview setting. A strong answer states assumptions, handles edge cases, explains trade-offs, and shows how to validate the result clearly.
Machine LearningTechnical Screen - OpenAIHardSoftware EngineerCheapest Daily Shirt Colors With No Color Repeated on Consecutive Days
Pick a blue, green or red shirt for each of n days so that the total price is as low as possible while never buying the same color on two consecutive days, and return the chosen color sequence. It tests dynamic programming over a small state space and reconstruction of the optimal choices.
Coding & AlgorithmsTechnical Screen - OpenAIHardSoftware EngineerCheapest Paint-Booth Color Schedule With No Repeat on Consecutive Cars
Choose one of three paint colors for each car on an assembly line to minimize total cost, never repeating a color on consecutive cars, and return the exact color chosen for each car.
Coding & AlgorithmsTechnical Screendynamic-programmingreconstructiongreedy-vs-dp - OpenAIMediumSoftware EngineerClarify a Machine Topology Coding Task
Implement and formalize an API to analyze distributed accelerator interconnect topologies, separating summary metrics from component-level graph structures and validating topologies like rings, cliques, and lines.
Software Engineering FundamentalsTechnical Screengraph-algorithmsbfsapi-design - OpenAIMediumSoftware EngineerClarify and Design Social-Graph Milestones
Clarify ambiguous social-graph milestones before designing follow and unfollow operations, consistent snapshots, and user recommendations. The discussion tests directed-edge semantics, snapshot guarantees, recommendation-policy choices, exclusions, deterministic tie rules, scale assumptions, and contract-focused testing.
Software Engineering FundamentalsOnsite - OpenAIHardSoftware EngineerCompute Infection Time in a Grid
This problem tests your ability to model state propagation in a 2D grid using Breadth-First Search (BFS) to determine the time required for a dynamic condition to cover all reachable nodes.
Coding & AlgorithmsTechnical ScreenBFSGraphSimulation - OpenAIHardMachine Learning EngineerCompute Matrix Prefix Products And Gradients
This question evaluates understanding of automatic differentiation for matrix operations, specifically forward and reverse-mode gradients for sequential, associative (but noncommutative) matrix products, together with algorithmic analysis of time and space complexity.
Machine LearningOnsite - OpenAIMediumSoftware EngineerCompute Plant Infection Stabilization
This problem tests your ability to simulate state propagation across a grid over discrete time steps and determine the minimum number of interventions required to contain an infection.
Coding & AlgorithmsTechnical ScreenSimulationGridBacktracking - OpenAIMediumSoftware EngineerCompute Plant Infection Time
This problem tests your ability to model a grid-based propagation process using Breadth-First Search (BFS), specifically handling multi-source initialization and obstacle avoidance.
Coding & AlgorithmsTechnical ScreenBFSGraphGrid - OpenAIHardData ScientistCompute churn with re-subscriptions
This problem tests your ability to reconstruct user subscription states over time from raw event logs, specifically identifying active status to calculate monthly churn rates.
Data Manipulation (SQL/Python)Technical ScreenSQLData ManipulationTime-series - OpenAIMediumMachine Learning EngineerCompute entropy and implement 1-NN
This question evaluates numerical stability and streaming computation for entropy estimation from logits, along with efficient vectorized linear-algebra implementation of 1-nearest-neighbor inference and its interpretation as a neural-network forward pass under different distance metrics.
Machine LearningOnsite - OpenAIMediumSoftware EngineerCompute infection spread time
This problem tests your ability to model a spreading process on a 2D grid using a multi-source Breadth-First Search (BFS) to determine the time required for a state to propagate across the entire space.
Coding & AlgorithmsOnsiteBFSGraphsGrid - OpenAIEasyData ScientistCompute signup rate and retention from raw logs
This question evaluates the ability to manipulate event-level logs to compute cohort metrics—specifically signup rate and D30 retention—testing proficiency in SQL/Python, event-time windowing, joins, aggregation, and understanding of upstream logging semantics.
Data Manipulation (SQL/Python)Technical Screen - OpenAIHardSoftware EngineerContiguous Extent Allocator for a Storage Volume, Then O(log n)
Build an allocator that hands out contiguous runs of blocks on a fixed-size volume and takes them back with coalescing, first with a simple sorted list and then with logarithmic reserve and release. Tests splitting/merging logic, choosing indexes for size and neighbor lookups, and keeping them consistent.
Software Engineering FundamentalsTechnical Screenallocatordata-structuresbalanced-bst - OpenAIMediumBackend EngineerConvert IPv4 Ranges to CIDR Blocks
This question evaluates understanding of IPv4 addressing, binary/bitwise manipulation, and the ability to summarize consecutive address ranges into minimal CIDR blocks, and belongs to the Coding & Algorithms domain for backend engineering roles.
Coding & AlgorithmsTechnical Screen - OpenAIMediumSoftware EngineerCount Connected Friend Groups
Determine the number of connected components in an undirected graph represented as an adjacency matrix using graph traversal or disjoint set union.
Coding & AlgorithmsTechnical Screengraphdfsbfs - OpenAIHardSoftware EngineerCount Events in a Trailing 15-Minute Window with a Fixed-Size Ring Buffer
Implement an event counter that returns how many events occurred in the trailing 15 minutes, using a fixed-size ring buffer of per-second buckets so memory stays bounded at any event rate. It tests circular buffers, stale-slot detection, window boundaries, late events and thread safety.
Software Engineering FundamentalsOnsite - OpenAIMediumSoftware EngineerCount Machines and Recover a Distributed Tree Topology
Implement a distributed tree discovery and aggregation protocol that counts reachable machines, recovers edges, handles network retries, detects unreachable subtrees, and validates tree invariants.
Software Engineering FundamentalsTechnical ScreenDistributed SystemsTreeGraph Traversal - OpenAIHardSoftware EngineerCount Ordered Four-Shop Road Paths That Visit One Shop of Each Type
Count the ordered routes through a town's road network that visit exactly one shop of each of four types, where consecutive shops must share a direct road and a route and its reverse count separately. Tests graph modeling, path enumeration under type constraints and careful counting on small graphs.
Coding & AlgorithmsOnline Assessment - OpenAIMediumMachine Learning EngineerDebug MiniGPT and Backpropagate Matmul
This question evaluates proficiency in debugging PyTorch transformer implementations, reasoning about attention mechanics and causal masking, implementing key–value caching for autoregressive decoding, and constructing provably correct backward passes for matrix multiplications and custom autograd.Functions.
Machine LearningTechnical Screen - OpenAIMediumMachine Learning EngineerDebug Transformer and Add KV Cache
This problem tests your understanding of transformer architecture by requiring you to fix a broken attention mechanism and implement a Key-Value cache to optimize autoregressive inference.
Machine LearningOnsiteTransformersAttentionInference - OpenAIMediumMachine Learning EngineerDebug a Concurrent Job Scheduler
This question evaluates debugging and hardening skills for concurrent systems, focusing on detection and reasoning about race conditions, deadlocks, lock-contention hotspots, state-machine invariant enforcement, rate-limiting, retry semantics, and instrumentation for per-job metrics in a job scheduler.
Software Engineering FundamentalsTechnical Screen
OpenAI