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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 6931–6960 of 9403 results
- PinterestMediumData ScientistHow to Design a Proportional Randomized Sampler?
This question evaluates proficiency in randomized algorithms and probabilistic sampling, with emphasis on numerical precision, large-weight handling, and memory-versus-accuracy trade-offs. Commonly asked in Coding & Algorithms interviews for data-science roles, it assesses practical application ability grounded in conceptual understanding of numerical stability and relevant data-structure choices.
Coding & AlgorithmsOnsite - PinterestEasyData ScientistHow to evaluate a new Carousel feature
This question tests your ability to design an A/B test for a feed-based UI feature, focusing on metric selection, counter-metrics, and the identification of potential cannibalization effects.
Analytics & ExperimentationTechnical ScreenA/B TestingMetricsExperiment Design - PinterestMediumData ScientistHow would you evaluate a carousel launch?
This question tests your ability to design a comprehensive evaluation framework for a product feature launch, specifically focusing on metric selection, causal impact measurement, and addressing potential cannibalization effects.
Analytics & ExperimentationTechnical ScreenExperimentationMetricsProduct Analytics - PinterestMediumData ScientistImplement Binary Search for Policy Violation Logs
This question evaluates understanding of algorithmic search and data manipulation skills, specifically applying binary search over date-ordered logs and composing efficient queries using SQL and Python.
Data Manipulation (SQL/Python)Onsite - PinterestMediumData ScientistImplement Bootstrap and Jackknife Estimates on a DataFrame
Tests practical statistical computing skills by requiring the implementation of bootstrap confidence intervals and jackknife variance estimation for arbitrary metrics evaluated on pandas DataFrames.
Statistics & MathOnsitestatisticsresamplingbootstrap - PinterestMediumData ScientistImplement Data Structure for Top-K Elements in Streams
This question evaluates competency in streaming algorithms, dynamic data structures for maintaining top-K elements in real time, and scalability considerations for handling large or distributed input streams.
Coding & AlgorithmsOnsite - PinterestMediumData ScientistImplement Function to Return First n Prime Numbers
This question evaluates algorithmic problem-solving and basic number-theory competency by requiring generation of prime numbers with attention to correctness and performance characteristics.
Coding & AlgorithmsOnsite - PinterestMediumSoftware EngineerImplement Hierarchical Region Access Overrides
Design and implement a regional access control system that handles time-based access overrides on a static tree hierarchy with out-of-order updates.
Software Engineering FundamentalsTechnical ScreenTreeBinary SearchData Structures - PinterestMediumData ScientistImplement Jackknife and Random Choice
Implement weighted random selection from scratch and compute delete-1 jackknife estimates of parameter bias and standard error for an arbitrary statistical estimator.
Coding & AlgorithmsTechnical Screensamplingresamplingstatistics - PinterestMediumData ScientistImplement LRUCache with O(1) Operations and Thread Safety
This question evaluates a candidate's ability to implement a constant-time LRU cache and reason about thread-safety and concurrent access, testing data structure design and concurrency competencies in the Coding & Algorithms domain.
Coding & AlgorithmsOnsite - PinterestHardMachine Learning EngineerImplement Naive Bayes classifier from scratch
This question evaluates understanding of probabilistic classification, specifically competence in estimating class priors, feature likelihood parameters, and computing posterior scores for Naive Bayes variants.
Machine LearningOnline Assessment - PinterestMediumMachine Learning EngineerImplement a Sparse Matrix Class
Design and implement a memory-efficient sparse matrix class supporting entry retrieval, updates, addition, and matrix multiplication.
Coding & AlgorithmsTechnical Screensparse-matrixhash-tablelinear-algebra - PinterestHardMachine Learning EngineerImplement a Stateful Search Autocomplete Session
Design an interactive autocomplete system that tracks query frequencies, returns the top 3 ranking prefix matches per keystroke, and commits completed queries to dynamic history.
Coding & AlgorithmsTechnical ScreenTrieHash TableDesign - PinterestMediumSoftware EngineerImplement a min-heap column allocator
This question evaluates a candidate's competency in data structures (priority queues/min-heaps), online algorithm design for stream processing, and complexity and memory analysis.
Coding & AlgorithmsTechnical Screen - PinterestHardData ScientistImplement and Evaluate Pin Similarity in Python
Practice a DS-focused Python similarity question using Pin representations, cosine similarity, top-k ranking, and explicit edge-case handling. Extend the implementation discussion to vectorized scaling, approximate retrieval, offline ranking metrics, leakage checks, diversity, and online evaluation.
Data Manipulation (SQL/Python)Technical Screen - PinterestMediumData ScientistImplement and extend My Calendar III
This question evaluates competency in designing and implementing efficient dynamic interval data structures, handling correctness for duplicate and nested intervals, extending APIs with cancellation and point queries, and performing rigorous worst-case time/space analysis and resource-adaptation.
Coding & AlgorithmsTechnical Screen - PinterestHardMachine Learning EngineerImplement bagging with decision trees
This question evaluates a candidate's competency in ensemble learning and practical implementation skills, including bootstrap sampling, decision tree base learners, aggregation via majority voting with tie-breaking, and managing data using pure Python lists and standard library routines.
Machine LearningOnline Assessment - PinterestEasyData ScientistImplement np.random.choice
This problem tests your ability to implement weighted random sampling from an array, focusing on probability distribution handling and efficient selection algorithms.
Coding & AlgorithmsTechnical ScreenProbabilitySamplingAlgorithms - PinterestMediumSoftware EngineerImplement sparse matrix storage, addition, and multiplication
This problem tests your ability to design a memory-efficient representation for sparse matrices and implement arithmetic operations while leveraging the sparsity of the data.
Coding & AlgorithmsOnsiteArraysHash MapsLinear Algebra - PinterestMediumSoftware EngineerImplement stream line reader and settle balances
This question evaluates streaming I/O and buffered string-processing competency for Part 1 and transaction netting with balance computation for Part 2, covering skills in memory-bounded parsing, data-structure bookkeeping, and algorithmic flow reasoning.
Coding & AlgorithmsOnsite - PinterestMediumSoftware EngineerImplement string-based big integer multiplication
Implement multiplyStrings(a, b) to multiply two non-negative integers given as decimal strings, returning the product as a string without any big-integer or arbitrary-precision library. The solution covers grade-school O(n*m) long multiplication with linear memory, the Karatsuba and FFT/NTT scaling alternatives, correct carry and leading/trailing-zero handling, and a full edge-case test plan.
Coding & AlgorithmsOnsite - PinterestEasyMachine Learning EngineerImplement string-based rounding without floats
This question evaluates proficiency in string-based numeric processing, arbitrary-precision arithmetic concepts, precise rounding rules including deterministic tie-breaking, and handling of sign and decimal edge cases, and falls under the Coding & Algorithms domain.
Coding & AlgorithmsTechnical Screen - PinterestMediumSoftware EngineerImplement tap-to-infect color grid on iOS
This question evaluates proficiency in mobile UI architecture, grid data structures, connected-component algorithm reasoning, and state management concerns such as undo and memory/stack safety within the mobile app development and iOS domain.
Software Engineering FundamentalsOnsite - PinterestHardMachine Learning EngineerImplement trie-based autocomplete
This problem tests your ability to implement a space-efficient Trie data structure capable of storing strings along with associated weights to return top-k suggestions for a given prefix.
Coding & AlgorithmsOnsiteTrieData StructuresStrings - PinterestMediumData ScientistImplement weighted random choice
This problem tests your ability to implement efficient weighted random selection, specifically focusing on cumulative distribution functions and binary search to achieve optimal query performance.
Coding & AlgorithmsTechnical ScreenAlgorithmsProbabilityBinary Search - PinterestMediumSoftware EngineerInsert Operators to Reach a Target
Tests backtracking with operator precedence handling and operand formatting to construct all valid arithmetic expressions evaluating to a target value.
Coding & AlgorithmsOnsitebacktrackingrecursionstring - PinterestMediumData ScientistInterpret A/B results for video-pin increase
This question evaluates statistical inference and experimentation skills, including A/B test hypothesis formulation with a predefined MDE, estimation of absolute and relative lift with confidence intervals, proportion testing for CTR and retention, sample ratio mismatch detection, and multiple-comparison adjustments.
Analytics & ExperimentationTechnical Screen - PinterestHardData ScientistInvestigate Homepage Experiment Without Control Group: Methods and Metrics
Evaluates quasi-experimental analysis and product-metric judgment after a homepage launch lacks a randomized control. Strong answers compare matching and propensity weighting, audit experiment hygiene, choose metrics, and diagnose mixed CTR results.
Analytics & ExperimentationOnsite - PinterestHardSoftware EngineerKeep Merchant Addresses, Social Followers, and Wiki Facts Up to Date
Design a high-scale merchant data enrichment platform that ingests, reconciles, and maintains up-to-date business attributes (addresses, social metrics, wiki metadata) across heterogeneous third-party sources with strong provenance and fault tolerance.
System DesignOnsitesystem-designdistributed-systemsdata-pipelines - PinterestHardSoftware EngineerList All Plus/Times Expressions Reaching a Target Under Operator Precedence
Tests backtracking and state tracking with operator precedence to evaluate and enumerate arithmetic expressions using addition and multiplication.
Coding & AlgorithmsOnsiteBacktrackingRecursionMath
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