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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 2821–2850 of 3640 results
- 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 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 - 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 - 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 - 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 - 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 - 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 - 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 - 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 - 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 - 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 - PinterestMediumData ScientistMaximize Non-Overlapping Task Scheduling Efficiency
This question evaluates understanding of interval scheduling and resource optimization, focusing on reasoning about time intervals and conflict-free selection of tasks.
Coding & AlgorithmsOnsite - PinterestMediumData ScientistMeasure Billboard Campaign Impact: Design, Bias, Test Strategy
This question assesses your ability to design a quasi-experimental framework for measuring the offline impact of an online brand campaign on user acquisition, accounting for external noise and selection bias.
Analytics & ExperimentationOnsiteCausal InferenceGeo-ExperimentsMetric Design - PinterestMediumSoftware EngineerMinimum Transfers Between Pin Boards
Tests breadth-first search and graph modeling skills by finding the shortest path across overlapping collections without constructing a dense graph between every pair.
Coding & AlgorithmsOnsiteBFSGraphHash Map - PinterestMediumData ScientistOptimize Hyper-parameter Search to Prevent Combinatorial Explosion
Evaluates Python grid-search generation and hyperparameter optimization strategy. Strong answers yield lazy Cartesian-product combinations and discuss random search, Bayesian optimization, pruning, early stopping, and budget limits.
Machine LearningOnsite - PinterestMediumMachine Learning EngineerRank Newly Launched Ads Under Cold Start
Design a machine learning system to rank and explore cold-start ads launched within the past seven days, balancing marketplace revenue, user engagement, and advertiser budget delivery.
ML System DesignOnsiteml system designcold startad tech - PinterestMediumSoftware EngineerReason About Nested JSON Schema Validation
Design and implement a recursive JSON schema validator that checks nested objects and arrays, enforces required properties, and returns precise failure paths for validation errors.
Software Engineering FundamentalsOnsiteJSON SchemaRecursionTree Traversal - PinterestMediumSoftware EngineerReconstruct an Itinerary from Flight Tickets
Tests graph modeling, depth-first search (DFS), and Hierholzer's algorithm to construct an Eulerian path with lexicographical tie-breaking.
Coding & AlgorithmsOnsiteGraphDFSEulerian Path - PinterestMediumSoftware EngineerReconstruct route from unordered travel tickets
This problem tests your ability to model a graph where each edge represents a transition, requiring you to find a valid linear sequence that visits every node exactly once.
Coding & AlgorithmsOnsiteGraphsHash MapLinked List - PinterestMediumSoftware EngineerSettle debts with minimal transactions
Pinterest software-engineer onsite coding question: given a list of debts as (debtor, creditor, amount) triples, return settlement transfers that clear every net balance using the minimum number of transactions. It tests reducing to net balances, recognizing the problem is NP-hard, backtracking with pruning to find the optimum for small N, and a heap-based greedy heuristic plus correctness and time/space complexity analysis for large, skewed debt graphs.
Coding & AlgorithmsOnsite - PinterestMediumData ScientistSize an Opportunity and Present It with Clear Visuals
Tests your ability to size an ambiguous product opportunity using top-down and bottom-up estimation, stress-test core assumptions with sensitivity analysis, and design executive-ready visuals to guide strategic investment decisions.
Analytics & ExperimentationOnsiteopportunity sizingproduct analyticsdata visualization
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