| 1 | regularization vs validationGoogle DeepMind 1Distinguish regularization from validation: when is each the right tool? | The Elements of Statistical Learning, 2nd EditionAn Introduction to Statistical Learning (with Applications in Python)ESL ch.7 model assessment; ISLP resampling vs shrinkage chapters |
| 1 | softmax cross-entropy gradientGoogle DeepMind 1Derive the gradient of cross-entropy loss with softmax inputs, and explain why we fuse them numerically. | Building makemore Part 4: Becoming a Backprop NinjaCS231n notes: Backpropagation, IntuitionsManual softmax-cross-entropy backward and the fused stable form |
| 1 | SVD in deep learningGoogle DeepMind 1Explain the SVD and give two places it shows up in modern deep learning. | 18.065 Matrix Methods in Data Analysis, Signal Processing, and Machine Learning (Spring 2018)LoRA: Low-Rank Adaptation of Large Language ModelsMuon: An optimizer for hidden layers in neural networksSVD/low rank; LoRA and Muon orthogonalisation as modern uses |
| 1 | coin flips until two headsGoogle DeepMind 1On average, how many fair coin flips until you see two heads in a row? Walk me through it. | Statistics 110: Probability (lectures)Fifty Challenging Problems in Probability with SolutionsFirst-step analysis and waiting-for-pattern problems |
| 1 | Q-learning vs policy gradientsGoogle DeepMind 1When would you choose Q-learning over policy gradients, and vice versa? | Reinforcement Learning: An Introduction (2nd ed.)Sutton & Barto Q-learning and policy-gradient chapters; Spinning Up comparison |
| 1 | explaining classifier rejectionGoogle DeepMind 1You have a binary loan-approval classifier and limited access to feature weights. How do you explain a rejection? | A Unified Approach to Interpreting Model Predictions (SHAP)SHAP attributions and counterfactual explanations for black-box decisions |
| 1 | rental listing recommendationsGoogle DeepMind 1Design a personalised recommendation system for rental listings using demographics, property metadata, amenities, price, reviews and locatio… | Machine Learning System Design InterviewDeep Learning Recommendation Model for Personalization and Recommendation Systems (DLRM)Similar-listings case study; sparse/dense feature ranking model |
| 1 | commercial break timing classifierGoogle DeepMind 1Design a classifier that predicts the optimal moment to insert a commercial break in a video. | TransNet V2: An effective deep network architecture for fast shot transition detectionDesigning Machine Learning SystemsShot-boundary candidates plus ML design framing of labels and metrics |
| 1 | product search recallGoogle DeepMind 1How would you improve product search results, focusing on the fraction of relevant documents retrieved (recall)? | Embedding-based Retrieval in Facebook SearchEmbedding retrieval, hard negatives and hybrid retrieval to raise recall |
| 1 | justifying neural network useGoogle DeepMind 1Justify using a neural network for a given problem: what do you need to know about the network, dataset, timeline and business context? | Rules of Machine Learning: Best Practices for ML EngineeringDesigning Machine Learning SystemsHeuristics first, when complexity pays off; business and data framing |
| 1 | ETA data sufficiencyGoogle DeepMind 1Do 1 million Seattle ride trips suffice to build an accurate ETA prediction model? How would you decide? | DeeprETA: An ETA Post-processing System at ScaleThe Elements of Statistical Learning, 2nd EditionUber residual ETA model; learning curves and model assessment |
| 1 | offline AUC vs online A/BMeta MSL 1Your ads CTR model shows a 2% offline AUC gain, but the online A/B is revenue-neutral with worse calibration. What is going on, and what do … | Practical Lessons from Predicting Clicks on Ads at FacebookTrustworthy Online Controlled Experiments: A Practical Guide to A/B TestingCalibration and normalised entropy in ads; offline-online metric divergence |
| 1 | Instagram Reels recommendationsMeta MSL 1Design the recommendation system for Instagram Reels. | Scaling the Instagram Explore recommendations systemMachine Learning System Design InterviewInstagram Explore/Reels multi-stage funnel; video recommendation case |
| 1 | news feed rankingMeta MSL 1Design a personalised news-feed ranking system / the “next post” logic for Facebook's feed. | News Feed ranking, powered by machine learningMachine Learning System Design InterviewFeed multi-event value model; personalised news feed case |
| 1 | Facebook Ads recommendationMeta MSL 1Design a recommendation system for Facebook Ads, and an evaluation framework for ads ranking. | Practical Lessons from Predicting Clicks on Ads at FacebookDeep Learning Recommendation Model for Personalization and Recommendation Systems (DLRM)CTR model, calibration, evaluation metrics; DLRM ranking |
| 1 | Instagram Story ML componentsMeta MSL 1Design the ML components behind an Instagram Story feature. | Scaling the Instagram Explore recommendations systemNews Feed ranking, powered by machine learningMeta multi-stage ranking and multi-task event prediction applied to Stories |
| 1 | Marketplace listing classificationMeta MSL 1Design an end-to-end classification pipeline for Marketplace listings. | Designing Machine Learning SystemsMachine Learning System Design InterviewLabelling, class imbalance, evaluation pipeline; classification case studies |
| 1 | translation model serviceMeta MSL 1Design a language translation model / service. | No Language Left Behind: Scaling Human-Centered Machine TranslationNLLB data, model, evaluation and serving; GNMT as baseline |
| 1 | harmful content detectionMeta MSL 1Design the harmful-content detection system for Facebook and Instagram uploads. | Machine Learning System Design InterviewA Holistic Approach to Undesired Content Detection in the Real WorldHarmful-content detection case; rare-class labelling and calibration |
| 1 | KL divergence continuousOpenAI 1Implement KL divergence for continuous distributions (formula provided; you must integrate it and interpret the result). | Auto-Encoding Variational BayesProbabilistic Machine Learning: An IntroductionClosed-form Gaussian KL derivation; continuous KL definitions |
| 1 | expected iterations probabilisticOpenAI 1Calculate the expected number of iterations for a probabilistic function. | Statistics 110: Probability (lectures)CS109: Probability for Computer Scientists (Autumn 2026)Geometric distribution and first-step analysis for expected iterations |
| 1 | cross-entropy minimum errorOpenAI 1Find the minimum error of a distribution using cross entropy (formula provided). | Information Theory, Inference, and Learning AlgorithmsGibbs' inequality: cross-entropy minimised at the true distribution |
| 1 | custom layer gradient derivationUnspecified frontier 1Derive the gradients for a specific custom layer (rather than "explain backprop"). | Derivatives, Backpropagation, and VectorizationBuilding makemore Part 4: Becoming a Backprop NinjaGeneralised Jacobians and manual backward for arbitrary layers |
| 1 | DeepMind fundamentals quiz roundGoogle DeepMind 1Rapid-fire quiz on undergraduate fundamentals (formal linear algebra, calculus, probability definitions). | Deep LearningProbability CheatsheetGoogle DeepMind Interview Notes (quizzes and design prompts with solutions)Goodfellow part I, cheatsheet, quiz-format practice |
| 1 | noisy annotator labelsOpenAI 1Noisy Annotators (3 parts) | OpenAI Interview Notes (problems with solutions)Confident Learning: Estimating Uncertainty in Dataset LabelsReference solution plus confident-learning noise estimation |
| 1 | Las Vegas restart strategyOpenAI 1Restart Strategies under a Known Mean (Las Vegas) (6 oral parts) | OpenAI Interview Notes (problems with solutions)Optimal Speedup of Las Vegas AlgorithmsRestart-strategy oral solution and Luby optimal restart result |
| 1 | probability linear algebra quizGoogle DeepMind 1Maths Quiz: Probability, Statistics and Linear Algebra (12 questions / 45–60 min) | Google DeepMind Interview Notes (quizzes and design prompts with solutions)Statistics 110: Probability (lectures)Full quiz with solutions; Stat 110 for the probability items |
| 1 | matrix stats info theory quizGoogle DeepMind 1Maths Quiz: Matrix Computation, Statistical Tests and Information Theory (12 questions / 45–60 min) | Google DeepMind Interview Notes (quizzes and design prompts with solutions)18.05 Introduction to Probability and Statistics (Spring 2022)Information Theory, Inference, and Learning AlgorithmsQuiz with solutions; 18.05 tests; MacKay information theory |
| 1 | ML fundamentals quizGoogle DeepMind 1ML Fundamentals: Metrics, Losses, Optimisers and Regularisation (15 questions / 60 min) | Google DeepMind Interview Notes (quizzes and design prompts with solutions)Introduction to Machine Learning Interviews BookFundamentals quiz solutions; Huyen metrics, losses and training chapters |
| 1 | molecule pair reaction predictionGoogle DeepMind 1ML Design: Predicting a Reaction Factor for Pairs of Molecules (45–60 min) | Google DeepMind Interview Notes (quizzes and design prompts with solutions)Neural Message Passing for Quantum ChemistryMolecule design reference solution; MPNN and scaffold splits |
| 1 | AdamW decoupled weight decayMistral 1Explain Adam and AdamW. Why is adding an L2 penalty to the loss generally different from decoupled weight decay under Adam? | Decoupled Weight Decay Regularization (AdamW)How to set AdamW's weight decay as you scale model and dataset sizeDecoupled decay derivation; how to set decay with scale |
| 1 | diffusion forward reverseMistral 1Explain the forward and reverse processes of diffusion models. | Denoising Diffusion Probabilistic ModelsMIT 6.S184: Introduction to Flow Matching and Diffusion Models (2026)DDPM processes; flow/SDE framing of forward and reverse |
| 1 | NSFW output detectionOpenAI 1ML system design: design a system to detect NSFW content in ChatGPT outputs. | A Holistic Approach to Undesired Content Detection in the Real WorldConstitutional Classifiers: Defending against Universal Jailbreaks across Thousands of Hours of Red TeamingModeration classifier design; streaming output classifiers on LLM text |
| 1 | Bayes spam base rateOpenAI 1Probability: spam detector with 99% TPR, 2% FPR, 10% base rate — probability a flagged email is spam? | CS109: Probability for Computer Scientists (Autumn 2026)Statistics 110: Probability (lectures)Bayes' rule with base rates; worked conditional-probability examples |