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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.
- 9403
- Questions
- 546
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- 11
- Topics
- 8
- Languages
Showing 361–390 of 9403 results
- AmazonMediumApplied ScientistCompute and Explain Mean and Variance
This question tests your understanding of statistical estimators for mean and variance, the derivation of Bessel's correction, catastrophic cancellation in naive computations, and numerically stable single-pass algorithms like Welford's.
Statistics & MathOnsiteStatisticsNumerical AnalysisAlgorithms - AmazonMediumData ScientistCompute and interpret quantile loss vs RMSE
This question tests the ability to distinguish between point-prediction error metrics and quantile loss, and the practical implications of choosing an evaluation metric in the context of asymmetric business costs.
Statistics & MathTechnical ScreenStatisticsForecastingLoss Functions - AmazonMediumData ScientistCompute array modes with ties and no-mode rule
This question evaluates algorithm design and data-structure skills—frequency counting, hashing, and handling edge cases such as ties and a no-mode rule—within the coding and algorithms domain for data scientist roles.
Coding & AlgorithmsTechnical Screen - AmazonMediumData ScientistCompute daily work hours from in/out events
This question evaluates a candidate's ability to manipulate time-series punch-event data, including temporal pairing of in/out events, splitting shifts across calendar days, rounding and aggregating hours, and detecting data-quality issues such as overlaps or orphaned events using SQL or Python.
Data Manipulation (SQL/Python)Onsite - AmazonMediumSoftware EngineerCompute delay times in priority array
This question evaluates algorithmic efficiency in array processing, specifically reasoning about nearest-smaller relationships and the use of auxiliary structures to achieve subquadratic performance.
Coding & AlgorithmsOnline Assessment - AmazonMediumSoftware EngineerCompute fruit spoilage time in a grid
This question evaluates a candidate's understanding of graph traversal concepts, grid-based state propagation, and reachability analysis in time-evolving systems.
Coding & AlgorithmsOnsite - AmazonMediumData ScientistCompute join counts and window ranks
This question evaluates SQL data-manipulation and analytic competencies including join semantics, set operations, window functions, view versus materialized view trade-offs, key and partition design, and query-tuning techniques in the Data Manipulation (SQL/Python) domain.
Data Manipulation (SQL/Python)Onsite - AmazonMediumSoftware EngineerCompute maximum distinct-product pickup days
This question evaluates a candidate's understanding of greedy and resource-allocation strategies along with combinatorial reasoning to maximize operations under discrete constraints.
Coding & AlgorithmsOnline Assessment - AmazonEasySoftware EngineerCompute minimal operations and optimal server pairing
This two-part question evaluates array manipulation and optimization skills—specifically range-update minimization to enforce a nondecreasing sequence and greedy pairing/matching to maximize summed primary resources—testing algorithm design, complexity reasoning, and constraint handling.
Coding & AlgorithmsOnline Assessment - AmazonMediumSoftware EngineerCompute optimal locker placement with obstacles
This interview question evaluates algorithm design, data structures, correctness, complexity, edge cases, and implementation details in a realistic interview setting. A strong answer for Compute optimal locker placement with obstacles states assumptions, handles edge cases, explains trade-offs, and shows how to validate the result clearly.
Coding & AlgorithmsOnsite - AmazonMediumData ScientistCompute p-values, CIs, and adjust multiples
This question evaluates a candidate's proficiency in statistical inference, covering hypothesis testing and test selection, confidence interval construction, multiple-testing corrections, error types, and asymptotic reasoning.
Statistics & MathTechnical Screen - AmazonMediumSoftware EngineerCompute peak parking lot occupancy intervals
This question evaluates a candidate's competency in temporal interval reasoning, event-stream processing, and handling incomplete or unsorted logs to determine peak concurrent occupancy.
Coding & AlgorithmsTechnical Screen - AmazonMediumSoftware EngineerCompute product excluding index without division
This question evaluates array-manipulation and algorithmic problem-solving skills, focusing on computing a product-for-each-index using prefix and postfix accumulation concepts while reasoning about edge cases such as zeros, negative numbers, and integer overflow.
Coding & AlgorithmsOnsite - AmazonMediumSoftware EngineerCompute reachability and minimal-time same-type scheduling
This prompt evaluates integer reachability and invariant reasoning via repeated additive transformations (testing number-theoretic reachability and state-space analysis) alongside resource-aware scheduling and grouping logic for minimizing completion time under type and memory constraints, and it falls under the Coding & Algorithms domain.
Coding & AlgorithmsOnline Assessment - AmazonMediumSoftware EngineerCompute shortest path with obstacles
This interview question evaluates algorithm design, data structures, correctness, complexity, edge cases, and implementation details in a realistic interview setting. A strong answer for Compute shortest path with obstacles states assumptions, handles edge cases, explains trade-offs, and shows how to validate the result clearly.
Coding & AlgorithmsTechnical Screen - AmazonMediumSoftware EngineerCompute the Median After Each Stream Insertion
This problem tests your ability to maintain dynamic statistics in a data stream using efficient data structures to achieve logarithmic insertion and constant-time retrieval.
Coding & AlgorithmsOnsiteHeapsData StreamsSorting - AmazonEasySoftware EngineerCompute the Minimum Number of Meeting Rooms
This problem tests your ability to manage overlapping time intervals efficiently, requiring an understanding of sorting or priority queues to track resource utilization.
Coding & AlgorithmsTechnical ScreenSortingIntervalsGreedy - AmazonMediumSoftware EngineerCompute total revenue from greedy VM rentals
This problem tests your ability to use greedy strategies combined with efficient data structures to manage resource allocation and optimize revenue based on priority-based demand.
Coding & AlgorithmsTechnical ScreenGreedyData StructuresHeap - AmazonMediumSoftware EngineerCompute tree diameter
This question evaluates understanding of binary tree algorithms, recursion versus iterative traversal strategies, and competence in algorithmic analysis including time and space complexity and handling deep-recursion stack overflow when computing a tree's diameter.
Coding & AlgorithmsTechnical Screen - AmazonMediumSoftware EngineerCompute unique visitors per department from clicks
This question evaluates a candidate's skill in data manipulation and deduplication using SQL/Python, specifically mapping hierarchical product metadata to departments and computing unique user counts without double-counting, and is categorized under Data Manipulation (SQL/Python).
Data Manipulation (SQL/Python)Technical Screen - AmazonMediumData ScientistConsolidate and Rank Global Salaries in USD
This question evaluates data consolidation, currency normalization, and ranking competencies, measuring the ability to combine country-specific employee data and convert salaries into a common USD basis within the Data Manipulation (SQL/Python) domain.
Data Manipulation (SQL/Python)Technical Screen - AmazonMediumSoftware EngineerControl Robot Charging with Repeated Polling and Exclusive Station Assignments
Design a repeatedly invoked robot-charging controller with strict battery thresholds, exclusive station assignments, waiting robots, and safe command retries.
Software Engineering FundamentalsTechnical Screen - AmazonMediumSoftware EngineerCount Connected Components in an Undirected Graph
This question tests the ability to traverse an undirected graph using graph search algorithms to identify and count disjoint subgraphs.
Coding & AlgorithmsTechnical ScreenGraphsBFSDFS - AmazonMediumBusiness Intelligence EngineerCount Customers Buying Both 'Kindle' and 'Alexa'
This question evaluates proficiency in relational data manipulation and set-based reasoning, assessing SQL competency such as joins, aggregation, and identifying distinct customers who purchased multiple specified products.
Data Manipulation (SQL/Python)Onsite - AmazonMediumSoftware EngineerCount Customers Who Visited on Multiple Dates
Tests data manipulation, hash set/map aggregation, and date deduplication to identify users with repeat visits across distinct calendar days.
Coding & AlgorithmsTechnical ScreenHash TableCountingString - AmazonMediumSoftware EngineerCount Four-Neighbor Islands in a Binary Matrix
Count four-neighbor islands in a binary matrix and consider the connectivity state needed when rows arrive as a stream.
Coding & AlgorithmsOnline Assessment - AmazonMediumSoftware EngineerCount expressions reaching a target sum
This interview question evaluates algorithm design, data structures, correctness, complexity, edge cases, and implementation details in a realistic interview setting. A strong answer for Count expressions reaching a target sum states assumptions, handles edge cases, explains trade-offs, and shows how to validate the result clearly.
Coding & AlgorithmsOnsite - AmazonMediumSoftware EngineerCount partitions and equal-cost packages
This question evaluates string-processing and combinatorial counting skills, including tracking distinct-character occurrences across contiguous partitions and using frequency-based pairing logic on arrays to form equal-cost packages.
Coding & AlgorithmsOnline Assessment - AmazonMediumSoftware EngineerCount regions with DFS
This question evaluates proficiency in graph traversal and grid-based connected-component detection using depth-first search on a binary m x n grid, along with algorithmic complexity analysis and techniques to avoid revisiting cells.
Coding & AlgorithmsTechnical Screen - AmazonMediumSoftware EngineerCount the Distinct Binary Search Tree Shapes for Keys 1 to n
Count how many structurally different binary search trees can store the keys 1 through n exactly once, for n up to 19. It tests reasoning about how tree shapes decompose and counting combinatorial structures efficiently instead of building every tree.
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