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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.
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Showing 6901–6930 of 9403 results
- PinterestMediumSoftware EngineerDesign highly available blob storage service
This question evaluates a candidate's competency in designing scalable, durable, and highly available blob/object storage systems, encompassing distributed systems architecture, data modeling for buckets and objects, metadata management, partitioning and routing, fault tolerance strategies, consistency models, large-object transfer patterns, security controls, and operational concerns like monitoring and capacity planning. Commonly asked in the System Design domain to assess practical application of architectural patterns and trade-offs—horizontal scalability, durability versus latency, consistency guarantees, and operational resilience—it primarily tests practical system-design skills grounded in conceptual understanding of distributed systems.
System DesignOnsite - PinterestHardData ScientistDesign metrics and experiment for Shopping launch
This question evaluates a data scientist’s competency in experimental design and product analytics, including metric selection and precise definitions, guardrail and funnel diagnostics, spillover and novelty handling, power/MDE estimation, and multi-objective decision framing.
Analytics & ExperimentationTechnical Screen - PinterestMediumMachine Learning EngineerDesign notification and feed recommenders
This question tests the ability to design a dual-purpose recommendation architecture capable of handling real-time push notifications and personalized feed updates at scale.
ML System DesignOnsiteRecommender SystemsRankingScalability - PinterestHardData ScientistDesign rigorous A/B test and causal analysis
This question evaluates a data scientist's competency in experimental design, sample-size and power calculations, variance-reduction methods (e.g., CUPED), sequential testing and alpha spending, clustering and interference effects, SRM checks, and causal identification strategies such as DID, IV, and RDD within the Statistics & Math domain.
Statistics & MathOnsite - PinterestMediumData ScientistDetermine Pin Connections Through Common Boards
This question evaluates graph modeling and connectivity concepts, including representing boards and pins as relationships and reasoning about reachability and minimal connection paths.
Coding & AlgorithmsOnsite - PinterestMediumSoftware EngineerDetermine equality of arbitrarily nested sets
This question evaluates understanding of nested data structures and set semantics, including canonicalization, hashing, recursion, handling of edge cases, unit-test design, and time/space complexity analysis.
Coding & AlgorithmsTechnical Screen - PinterestHardData ScientistDiagnose CTR drop after recommendation launch
This question evaluates a data scientist's competency in experiment diagnosis, metric and guardrail definition, instrumentation validation, segmentation analysis, and causal reasoning for recommender-system impacts.
Analytics & ExperimentationOnsite - PinterestMediumData ScientistEstimate a Launch Impact with Difference in Differences
Tests your ability to design and evaluate a regional quasi-experiment using Difference-in-Differences (DiD), validate key identifying assumptions, structure robust inference, and address modern complications such as staggered rollout and network spillovers.
Analytics & ExperimentationOnsiteDifference-in-DifferencesCausal InferenceQuasi-Experiments - PinterestHardData ScientistEstimate billboard reach and impressions
This question evaluates probabilistic modeling and statistical inference skills applied to audience measurement and attribution, covering Poisson-based frequency modeling, visibility-adjusted impressions, panel-based deduplication and expansion, uncertainty propagation (delta method/bootstrap), and Markov-chain attribution within the Statistics & Math / Data Science domain. It is commonly asked to test the ability to convert traffic and visibility inputs into quantitative reach and impressions with propagated confidence intervals, reason about attribution via a 3-state Markov chain, identify measurement biases, and demonstrates both conceptual understanding and practical application through numerical estimation and sensitivity analysis.
Statistics & MathOnsite - PinterestMediumData ScientistEvaluate Carousel and Billboard Lift
This question tests your ability to design an A/B test for multi-format advertising, specifically handling cannibalization and cross-format lift measurement.
Analytics & ExperimentationTechnical ScreenA/B TestingCausal InferenceMetrics - PinterestMediumData ScientistEvaluate Fresh Content and Video Experiments
This question evaluates competencies in metric design, experimental design, statistical inference, and product analytics—specifically defining and critiquing freshness metrics, formulating null and alternative hypotheses for content changes, interpreting A/B test results, and calculating sample size and power.
Analytics & ExperimentationTechnical Screen - PinterestMediumData ScientistEvaluate New Feed-Ranking Algorithm with A/B Testing
Pinterest experimentation prompt on evaluating a new feed-ranking algorithm, covering A/B hypotheses, daily active minutes, guardrails, sample size, MDE, experiment health, mid-test dips, and geo-based causal inference.
Analytics & ExperimentationOnsite - PinterestMediumMachine Learning EngineerExplain bias–variance, overfitting, and vanishing gradients
This question tests the conceptual understanding of the bias-variance tradeoff, methods for diagnosing and preventing overfitting, and the theoretical causes and architectural solutions for vanishing gradients in deep learning.
Machine LearningTechnical ScreenDeep LearningBias-Variance TradeoffRegularization - PinterestEasyMachine Learning EngineerExplain learning-rate fluctuation and vanishing gradients
This question evaluates a candidate's understanding of optimization dynamics (effects of learning rate on training stability) and backpropagation-related issues (vanishing gradients) in deep neural networks, assessing competencies in training behavior and gradient propagation within the Machine Learning domain.
Machine LearningTechnical Screen - PinterestHardMachine Learning EngineerExplain overfitting and how to prevent it
This question evaluates understanding of overfitting, the relationship between training and validation performance and generalization, and knowledge of regularization concepts including differences between L1 and L2 penalties.
Machine LearningTechnical Screen - PinterestHardMachine Learning EngineerExplain overfitting, underfitting, and regularization
This question tests the conceptual understanding of the bias-variance tradeoff and the practical application of regularization to balance model complexity and generalization error.
Machine LearningTechnical ScreenBias-VarianceRegularizationGeneralization - PinterestHardData ScientistExplain your ML project end-to-end
This question evaluates a data scientist's end-to-end machine learning competencies, including problem framing and metric justification, data sourcing and labeling, model selection and calibration, class-imbalance handling, deployment and monitoring, experimentation design, and post-mortem analysis; it is in the Machine Learning domain and tests both conceptual understanding and practical application across modeling and MLOps. It is commonly asked to assess an interviewee's ability to justify trade-offs, reason about operational constraints such as latency, fairness and cost, design valid evaluation and A/B testing strategies, and define measurable monitoring and rollback criteria.
Machine LearningTechnical Screen - PinterestEasySite Reliability EngineerFetch a Field from Two URLs, Extract Valid IP Addresses, and Rank Them by Count
A practical scripting exercise for a site reliability role: send GET requests with a required header to two URLs, pull a text field from each response, extract every valid IP address, and rank the addresses by how often they appear. It tests HTTP error handling, strict IPv4 validation, code reuse and deterministic sorting.
Software Engineering FundamentalsTechnical Screen - PinterestMediumSoftware EngineerFewest Buses to Ride Between Two Stops on Looping Bus Lines
A coding problem about bus lines that loop through fixed lists of stops: find the fewest buses a rider must board to travel from a source stop to a target stop, or report that the target cannot be reached. It tests modeling transfers between lines as a graph and keeping the search efficient when many lines share stops.
Coding & AlgorithmsOnsite - PinterestMediumSoftware EngineerFind First Prefix-Matching Word
This problem tests your ability to efficiently search through a collection of strings to find the first element that satisfies a specific prefix condition, emphasizing clean iteration and edge case management.
Coding & AlgorithmsTechnical ScreenStringsArraysIteration - PinterestMediumData ScientistFind available reservation time slots
This question evaluates a candidate's ability to reason about time-interval data and temporal normalization, testing competencies in interval manipulation, conflict detection, and algorithmic problem-solving for scheduling contexts.
Coding & AlgorithmsOnsite - PinterestMediumData ScientistFind list pair with maximum overlap
This question evaluates proficiency with set operations and similarity metrics (Jaccard), scalable algorithm design and complexity analysis for large datasets, and the ability to handle streaming updates and deterministic tie-breaking.
Coding & AlgorithmsOnsite - PinterestMediumSoftware EngineerFind minimum shuttle transfers
Find minimum shuttle transfers evaluates algorithm design, data structures, correctness, complexity, edge cases, and implementation details in a realistic interview setting. A strong answer states assumptions, handles edge cases, explains trade-offs, and shows how to validate the result clearly.
Coding & AlgorithmsOnline Assessment - PinterestMediumSoftware EngineerFind the Minimum Number of Coins for an Amount
Tests dynamic programming and breadth-first search techniques to find the minimum number of coin denominations required to reach a target value, including edge cases like zero and unreachable sums.
Coding & AlgorithmsOnsitedynamic-programmingbfsarrays - PinterestMediumData ScientistFind the Share of Power Listeners per Region from Play Events
Write a PostgreSQL query that, for a trailing 7-day window, classifies listeners per region as active or 'power' users based on how many distinct days they listened and whether they used at least three different playback devices on any single one of those days, then reports the power-user share per region.
Data Manipulation (SQL/Python)Technical Screensqlwindow-functionsaggregation - PinterestMediumData ScientistFind top video category by average time
This question evaluates a candidate's ability to perform data manipulation and aggregation in Python (pandas), covering skills such as filtering, handling nulls and nonpositive values, mapping categorical IDs to names, rounding numerical results, and applying tie-breaking rules.
Data Manipulation (SQL/Python)Technical Screen - PinterestMediumMachine Learning EngineerFirst Word Matching Each Prefix Query
This problem tests your ability to efficiently query a list of strings to find the first occurrence that matches a given prefix, focusing on optimal space-time tradeoffs using tree-based or map-based indexing.
Coding & AlgorithmsOnsiteTrieHash MapString Processing - PinterestMediumSoftware EngineerGenerate Attribute Combinations
Explain Cartesian-product generation for attribute choices while preserving mixed value types and making ordering, duplicates, and empty cases explicit.
Software Engineering FundamentalsTechnical Screen - PinterestMediumMachine Learning EngineerGenerate all hyperparameter combinations
This problem tests your ability to generate the Cartesian product of multiple lists, a fundamental task in grid search for hyperparameter tuning.
Coding & AlgorithmsTechnical ScreenCombinatoricsRecursionIteration - PinterestMediumMachine Learning EngineerHierarchical Access Control for an Advertising Platform
This problem tests graph traversal algorithms and efficient membership checking within a directed acyclic graph (DAG) representing hierarchical organizational permissions.
Coding & AlgorithmsOnsiteGraphsDAGBFS/DFS
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