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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
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- 11
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Showing 2671–2700 of 4616 results
- Mistral AIMediumSoftware EngineerExplain the Forward and Reverse Processes of Diffusion Models
Explain Gaussian diffusion corruption, timestep-conditioned denoising, noise-prediction training, iterative reverse sampling, latent representations, and guidance tradeoffs.
Machine LearningTechnical Screen - Mistral AIMediumSoftware EngineerKeep GPUs Fed with an Efficient Data-Preparation Pipeline
Diagnose GPU input starvation across storage, CPU preprocessing, batching, transfer, and synchronization, then improve bounded overlap while preserving data correctness.
Software Engineering FundamentalsTechnical Screen - Mistral AIMediumSoftware EngineerSet up a Python LLM dev environment
This question evaluates practical competencies in Python development environment setup, reproducible dependency management with lockfiles, virtual environment and interpreter management, secrets handling via environment variables, project structuring, and basic API integration.
Software Engineering FundamentalsTechnical Screen - MixpanelMediumData ScientistCalculate First-Week Retention by Signup Cohort
Compute first-week activity retention by signup-week cohort with all cohort users in the denominator and zero-retention cohorts included.
Data Manipulation (SQL/Python)Technical Screen - MixpanelMediumData ScientistCompare First-Week Retention by Plan Type
Compare first-week retention by recorded plan type with distinct-user counts, inclusive denominators, and four-decimal rates.
Data Manipulation (SQL/Python)Technical Screen - MixpanelMediumData ScientistCount Users Active After Signup
Count distinct users with at least one event on or after signup using a PostgreSQL query.
Data Manipulation (SQL/Python)Technical Screen - MixpanelMediumData ScientistCount Users Retained on Day Seven
Count users active on the seventh calendar day after signup, without double-counting repeated events.
Data Manipulation (SQL/Python)Technical Screen - MixpanelMediumSoftware EngineerGroup Events by an Ordered Attribute List
This problem tests recursive data structuring and hierarchical aggregation by mapping flat event logs to a nested tree of counts based on an ordered list of attributes.
Coding & AlgorithmsTechnical ScreenHash MapsRecursionData Aggregation - MixpanelMediumSoftware EngineerImplement precise string-based decimal addition
This question evaluates a candidate's proficiency in string-based arbitrary-precision arithmetic, including decimal alignment, fractional carry propagation, normalization of numeric strings, and analysis of time and space complexity.
Coding & AlgorithmsTechnical Screen - MixpanelMediumData ScientistValidate Features That Predict User Retention
Learn to evaluate retention features with leakage-safe time windows, cohort validation, baselines, ablations, and calibrated predictions.
Machine LearningTechnical Screen - ModalMediumSoftware EngineerExplain and Harden Two Shell Commands
Tests deep understanding of Unix shell semantics, process management, file permissions, and standard stream handling by diagnosing subtle failure modes in common shell one-liners and writing robust, production-grade replacements.
Software Engineering FundamentalsTechnical Screenbashlinuxsystems - ModalMediumSoftware EngineerProve an Incremental Shuffle Is Uniform
Tests formal inductive reasoning on randomized algorithms by proving the uniformity of the Fisher-Yates shuffle, and evaluates practical knowledge of common implementation pitfalls like off-by-one bounds and modulo bias.
Software Engineering FundamentalsTechnical Screenalgorithmsprobabilityfisher-yates - ModalMediumSoftware EngineerSort One Hundred Million Digits
Implement counting sort to order 100,000,000 single-digit integers using O(1) auxiliary space, and analyze performance from a hardware and memory-bandwidth perspective.
Software Engineering FundamentalsTechnical Screenalgorithmscounting-sortsystems - ModularHardSoftware EngineerFind the Critical Path
This question evaluates competency in graph algorithms and project scheduling, specifically reasoning about directed acyclic graphs, task dependencies, and accumulation of task durations to identify a critical path.
Coding & AlgorithmsTechnical Screen - MolocoMediumSoftware EngineerCan you visit all rooms and score parentheses?
The first problem evaluates graph traversal and reachability by modeling rooms and keys as an implicit graph, and it is commonly asked to assess reasoning about connectivity and exploration in graph-theoretic settings; this falls under the algorithms/graph theory domain and emphasizes practical application of traversal techniques.
Coding & AlgorithmsTechnical Screen - MolocoHardSoftware EngineerCompute subarray span for each element
This question evaluates array reasoning and competency in determining span-like influence regions under maximum-value constraints for each element, including handling circular-array extensions and scalability considerations.
Coding & AlgorithmsTechnical Screen - MolocoMediumData ScientistFind top advertisers and cost per KPI
This question evaluates proficiency in data manipulation and analytical SQL/Python skills, including aggregation, ranking with ties, dataset joins at a defined grain, date-based filtering relative to campaign launch dates, and handling division-by-zero scenarios when computing cost metrics.
Data Manipulation (SQL/Python)Technical Screen - MomentMediumFrontend EngineerBuild a Race-Free Memory Card Game in React
Work through the state and timing logic for a React memory-card game that remains correct under rapid clicks and restarts. The exercise examines stale closures, input locking, timeout cleanup, stable card identity, accessible interaction, and tests for race-prone transitions.
Software Engineering FundamentalsTechnical Screen - MongoDBHardSoftware EngineerBuild an Exactly-Once Crawler and Add Safe Concurrency
Build a crawler around a supplied fetch-and-parse API, then add bounded concurrency, atomic discovery, correct completion detection, and explicit failure semantics.
Software Engineering FundamentalsTechnical Screen - MongoDBMediumSoftware EngineerDesign iterator for sorted union
This problem tests your ability to design an iterator that merges multiple sorted streams of integers while performing on-the-fly deduplication using minimal extra memory.
Coding & AlgorithmsTechnical ScreenHeapIteratorsMerge Sort - MongoDBMediumSoftware EngineerEvaluate a Nested Predicate Expression Tree
Implement an evaluator for a serialized predicate expression tree against JSON documents, testing recursion, AST handling, and field resolution.
Software Engineering FundamentalsTechnical Screenrecursiontreesdesign - MongoDBMediumSoftware EngineerImplement a Lazy Union Iterator Over Two Strictly Sorted Iterators
Implement a UnionIterator that lazily merges two strictly sorted iterators of integers or strings into one strictly sorted iterator without duplicates, using constant extra memory. Tests iterator protocol design, one-element lookahead, cross-input deduplication, end-of-stream behavior and edge cases such as empty inputs.
Software Engineering FundamentalsTechnical Screen - MongoDBMediumSoftware EngineerImplement a sliding-window rate limiter (n requests per k seconds), then make it per key
Coding and design question from a technical screen: implement a rate limiter that admits at most n requests in any k-second sliding window, then make it thread-safe and key-specific. It tests window boundary semantics, amortized complexity, race conditions and locking, per-key state creation and memory bounds.
Software Engineering FundamentalsTechnical Screen - MongoDBMediumSoftware EngineerReason About Recursive Key Search in Nested JSON
Implement a recursive search function to extract all values associated with a given key from deeply nested JSON documents containing arbitrary combinations of dictionaries and lists.
Software Engineering FundamentalsTechnical ScreenRecursionJSONTree Traversal - MongoDBMediumSoftware EngineerSummarize background, challenge project, and failure
This prompt evaluates leadership, technical ownership, communication, system-design reasoning, and incident-analysis competencies by requesting a concise career narrative, a deep-dive into a challenging project (including constraints, trade-offs, architecture, validation, and metrics), and a meaningful failure retrospective.
Behavioral & LeadershipTechnical Screen - Morgan StanleyEasyData ScientistCompute win probability in coin-toss game
This question evaluates understanding of probability theory and stochastic processes, focusing on win probability in an alternating coin-toss game and reasoning about pattern occurrence and stopping times in random sequences.
Coding & AlgorithmsTechnical Screen - Morgan StanleyMediumData ScientistEstimate Greeks and hedging PnL
This question evaluates understanding of option Greeks (delta, gamma, vega), mental approximation of Gaussian probabilities, and the ability to reason about delta-hedged profit-and-loss under Black-Scholes model misspecification, categorized under Software Engineering Fundamentals for a Data Scientist role.
Software Engineering FundamentalsTechnical Screen - Morgan StanleyEasyData ScientistExplain forward contracts and options
This question evaluates understanding of financial derivatives—specifically forwards and options—assessing competency in financial instruments, contractual rights and obligations, pricing concepts, and how these concepts inform data-driven modeling for a Data Scientist role.
Software Engineering FundamentalsTechnical Screen - MorningstarEasyData ScientistExplain a stochastic process simply
This question assesses the candidate's ability to intuitively define a stochastic process, differentiate it from static probability models, and articulate fundamental properties like stationarity and the Markov property.
Statistics & MathTechnical ScreenStatisticsStochastic ProcessesTime Series - NVIDIAMediumSoftware EngineerClarify and Design a Streaming Top-K Tracker
This question tests the ability to design an efficient data structure for maintaining the top-K elements in a high-throughput stream with time-windowing requirements.
Software Engineering FundamentalsTechnical ScreenData StructuresAlgorithmsStreaming
Mistral AI
Mixpanel
Moloco
MongoDB
Morgan Stanley
NVIDIA