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Machine Learning 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 241–270 of 381 results

  • PinterestHardMachine Learning Engineer
    Prevent Vanishing Gradients in Deep Networks

    Tests a candidate's mathematical understanding of the vanishing gradient problem in deep neural networks and their ability to evaluate architectural mitigations including weight initialization, activation functions, residual connections, and normalization layers.

    Machine LearningTechnical ScreenDeep LearningOptimizationNeural Networks
  • PinterestHardMachine Learning Engineer
    Solve a 9x9 Sudoku puzzle

    This question evaluates algorithmic problem-solving skills focused on constraint satisfaction, state-space search, and implementation correctness for combinatorial puzzles.

    Coding & AlgorithmsTechnical Screen
  • PlaidMediumMachine Learning Engineer
    Design a Fraud Detection System

    This question evaluates competency in ML system design for fraud detection within fintech data-connectivity platforms, testing real-time scoring, feature engineering (including relational/graph signals), label strategy, model training and serving, and operational concerns such as latency, privacy, monitoring, and robustness.

    ML System DesignTechnical Screen
  • Point72MediumMachine Learning Engineer
    Design Features for Residual Volatility

    This problem tests the ability to decompose financial asset returns into systematic and idiosyncratic components and design features to capture residual volatility.

    Machine LearningTechnical ScreenTime-SeriesFinanceFeature Engineering
  • Point72MediumMachine Learning Engineer
    Find the Smallest String After One Decrement

    This question evaluates string manipulation, lexicographic ordering, and reasoning about local character transformations including wrap-around behavior.

    Coding & AlgorithmsTechnical Screen
  • RbcroyalbankMediumMachine Learning Engineer
    Navigate Conflict, Compromise, and a Revealed Weakness

    This set of behavioral prompts evaluates a candidate's ability to navigate professional friction, demonstrate self-awareness regarding technical limitations, and exercise judgment in collaborative software development.

    Behavioral & LeadershipTechnical ScreenBehavioralConflict ResolutionLeadership
  • RbcroyalbankMediumMachine Learning Engineer
    Process Operations for an In-Memory Key-Value Store

    This problem tests proficiency with hash map operations and handling data retrieval edge cases within an in-memory data store.

    Coding & AlgorithmsTechnical ScreenHash MapData StructuresAlgorithms
  • RedditMediumMachine Learning Engineer
    Build and evaluate click prediction models

    This question evaluates skills in supervised probabilistic modeling for click-through rate prediction, including model selection, calibration, evaluation metric choice, cross-validation, hyperparameter tuning, and production concerns like serving and monitoring.

    Machine LearningTechnical Screen
  • RedditMediumMachine Learning Engineer
    Design Comment Prediction Ranking System

    This question assesses the ability to design an end-to-end ML pipeline for ranking comments by predicted user engagement probability, balancing accuracy, latency, and system scalability.

    ML System DesignTechnical ScreenRankingRecommendation SystemsFeature Engineering
  • RedditEasyMachine Learning Engineer
    Design a Tennis Scoring System

    This problem tests your ability to model state transitions, encapsulate logic using object-oriented principles, and implement conditional rule-based scoring in a competitive game.

    Software Engineering FundamentalsTechnical ScreenObject-Oriented DesignState MachineLogic
  • RedditHardMachine Learning Engineer
    Explain and Reduce Position Bias in Ranking

    Assess understanding of position bias in click-based ranking systems, including formalizing the examination hypothesis, estimating observation propensities, training with Inverse Propensity Scoring (IPS), and designing counterfactual evaluation metrics.

    Machine LearningTechnical ScreenRankingRecommendationPosition Bias
  • RedditMediumMachine Learning Engineer
    Implement a simplified memcached server

    This problem tests your ability to design a thread-safe, in-memory key-value store and implement basic command parsing for an asynchronous network service.

    Coding & AlgorithmsTechnical ScreenConcurrencyData StructuresCaching
  • RobloxHardMachine Learning Engineer
    Design a real-time game recommendation system

    Design a real-time game recommendation system evaluates ML product requirements, data/labeling, modeling, serving architecture, evaluation, monitoring, and trade-offs in a realistic interview setting. A strong answer states assumptions, handles edge cases, explains trade-offs, and shows how to validate the result clearly.

    ML System DesignTechnical Screen
  • RobloxEasyMachine Learning Engineer
    Extend counter to per-client rate limiting

    This question evaluates competency in designing per-client, time-windowed rate limiting using efficient data structures for time-based eviction and counting within the Coding & Algorithms domain.

    Coding & AlgorithmsTechnical Screen
  • RobloxEasyMachine Learning Engineer
    Find the Most Frequent Log Call

    This question evaluates a candidate's ability to perform frequency analysis on sequences, demonstrating competency with data structures for counting occurrences and with algorithmic time and space complexity considerations.

    Coding & AlgorithmsTechnical Screen
  • RobloxEasyMachine Learning Engineer
    Implement recent-requests counter

    This question evaluates a candidate's ability to design efficient in-memory data structures and manage time-windowed event counting, testing algorithmic reasoning and performance optimization for high-throughput services.

    Coding & AlgorithmsTechnical Screen
  • RobloxMediumMachine Learning Engineer
    Level-Ordered Dependency Build Order

    This problem tests your ability to perform a Kahn’s algorithm-based topological sort while grouping tasks into parallelizable layers, ensuring cycle detection and dependency validation.

    Coding & AlgorithmsTechnical ScreenGraphBFSTopological Sort
  • RunwayHardMachine Learning Engineer
    Design a scalable video search system

    This interview question evaluates ML product requirements, data/labeling, modeling, serving architecture, evaluation, monitoring, and trade-offs in a realistic interview setting. A strong answer for Design a scalable video search system states assumptions, handles edge cases, explains trade-offs, and shows how to validate the result clearly.

    ML System DesignTechnical Screen
  • RunwayHardMachine Learning Engineer
    Implement n-gram model and select n

    This interview question evaluates core ML concepts, assumptions, math intuition, training/evaluation trade-offs, and practical failure modes in a realistic interview setting. A strong answer for Implement n-gram model and select n states assumptions, handles edge cases, explains trade-offs, and shows how to validate the result clearly.

    Machine LearningTechnical Screen
  • SamsungMediumMachine Learning Engineer
    Validate palindrome with constraints

    This question evaluates a candidate's ability to implement string-processing algorithms and two-pointer techniques under O(n) time and O(1) extra space constraints, including character filtering, case normalization, edge-case handling, and algorithmic complexity analysis.

    Coding & AlgorithmsTechnical Screen
  • Scale AIMediumMachine Learning Engineer
    Debug ML pipeline and build text parser

    This question evaluates practical machine learning engineering skills, including debugging unfamiliar codebases, parsing noisy text data, and identifying subtle defects such as train/test leakage or shape mismatches. It tests applied Python proficiency and systematic reasoning under time pressure, core competencies assessed in ML engineer technical interviews.

    Data Manipulation (SQL/Python)Technical Screen
  • Scale AIHardMachine Learning Engineer
    Explain Transformers, attention, decoding, RL, and evaluation

    This question evaluates understanding of transformer architectures, self- and cross-attention mechanisms, autoregressive decoding and sampling strategies, reinforcement learning–based fine-tuning (RLHF), evaluation methodologies, and training/inference optimization techniques.

    Machine LearningTechnical Screen
  • Scale AIMediumMachine Learning Engineer
    Implement universal adversarial attack on GPT-2

    Machine learning robustness prompt on safely evaluating universal adversarial prompts for GPT-2, covering threat modeling, differentiable optimization concepts, transferability, metrics, safety controls, and mitigation strategies without deployment-ready jailbreak details.

    Machine LearningTechnical Screen
  • ShopifyMediumMachine Learning Engineer
    Build a fraud detection model

    Design an end-to-end machine learning system for real-time transaction fraud detection, covering label formulation under delayed feedback, feature design, threshold selection, and continuous monitoring.

    Machine LearningTechnical Screenfraud-detectionmachine-learningsystem-design
  • ShopifyMediumMachine Learning Engineer
    Build an Automatic Refund Decision System in a Pair-Programming Session

    A pair-programming exercise to build an automatic refund system for an online store, combining light system design with working code across several incremental steps. It tests domain modeling, pluggable eligibility rules, preventing over-refunds and duplicate payouts on retries, and explaining design choices as you code.

    Software Engineering FundamentalsTechnical Screen
  • ShopifyMediumMachine Learning Engineer
    Explain your career and flagship project

    This question evaluates a candidate's ability to narrate career progression, demonstrate leadership and ownership, articulate technical decisions and trade-offs, and show production-grade machine learning engineering through a flagship-project deep dive that includes problem definition, business impact, ownership, and success metrics.

    Behavioral & LeadershipTechnical Screen
  • ShopifyMediumMachine Learning Engineer
    Implement a Capacity-Bounded Cache

    This question tests the ability to implement a Least Recently Used (LRU) cache, requiring efficient O(1) time complexity for both data retrieval and insertion through the combination of a hash map and a doubly linked list.

    Coding & AlgorithmsTechnical ScreenHash MapLinked ListCache
  • ShopifyMediumMachine Learning Engineer
    Simulate a rover fleet

    This problem tests your ability to manage state in a 2D grid simulation, coordinate multiple entities with movement logic, and enforce collision-avoidance constraints.

    Coding & AlgorithmsTechnical ScreenSimulationGridCollision Detection
  • SiemensMediumMachine Learning Engineer
    Batch and Pad Variable-Length Vectors with Optional Final-Batch Dropping

    Implement an ordered data pipeline function that partitions variable-length numerical sequences into batches, applies batch-local right padding, handles empty vectors, and optionally discards incomplete final batches.

    Coding & AlgorithmsTechnical Screendata-pipelinesarraysmachine-learning
  • SiemensMediumMachine Learning Engineer
    Compare GRPO and PPO and Explain Sparse Versus Dense Rewards

    This question evaluates your understanding of modern reinforcement learning post-training techniques for language models, focusing on GRPO versus standard PPO and the trade-offs between sparse outcome rewards and dense process supervision.

    Machine LearningTechnical ScreenReinforcement LearningLLM Post-TrainingPPO