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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
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- 546
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- 11
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Showing 241–270 of 3640 results
- AmazonMediumData ScientistFind Top-3 Salaries Per Department Using SQL
This question evaluates SQL data manipulation competency, focusing on group-wise aggregation, ordering, and selecting the top-N salary values within each department.
Data Manipulation (SQL/Python)Onsite - AmazonHardSoftware EngineerFind a Valid Course Order
This problem tests your ability to detect cycles in a directed graph and perform a topological sort to resolve dependencies.
Coding & AlgorithmsOnsiteGraphsTopological SortKahn's Algorithm - AmazonMediumSoftware EngineerFind longest common contiguous subarray
This question evaluates a candidate's proficiency in array and substring algorithm design, including concepts such as dynamic programming, hashing, and efficient search techniques.
Coding & AlgorithmsOnsite - AmazonMediumSoftware EngineerFind returning users from access logs
This question evaluates skills in time-series data processing, timestamp parsing and time-zone normalization, scalable stream or batch handling for logs that exceed memory, algorithmic complexity analysis, and test-case design for edge conditions such as midnight boundaries and duplicate events.
Coding & AlgorithmsOnsite - AmazonMediumApplied ScientistFind shortest path in a grid with obstacles
This question evaluates understanding of pathfinding in grid-based environments, graph traversal concepts, and algorithmic complexity when navigating obstacles and boundary constraints in an unweighted 2D search space.
Coding & AlgorithmsOnsite - AmazonHardSoftware EngineerFind the Closest Version by Date
This problem tests your ability to efficiently search through chronologically ordered records and handle binary search logic with custom comparison rules.
Coding & AlgorithmsOnsiteBinary SearchArraysAlgorithms - AmazonMediumSoftware EngineerFind the Kth Smallest Value in a Binary Search Tree
Deserialize a level-order serialized binary search tree and find its kth smallest element using an efficient in-order traversal.
Coding & AlgorithmsOnsitebinary-search-treetree-traversalstack - AmazonMediumSoftware EngineerFind the Minimum Processing Rate to Meet a Deadline
This problem tests the ability to determine a minimum threshold using binary search on the answer space, combined with modular arithmetic and ceiling division.
Coding & AlgorithmsOnsiteBinary SearchMathOptimization - AmazonHardSoftware EngineerFind the Most Common Visit Pattern
This problem tests your ability to process chronological event data to identify the most frequent 3-step sequence, requiring efficient data structures to handle large volumes of user logs.
Coding & AlgorithmsOnsiteHash MapSortingSliding Window - AmazonMediumSoftware EngineerFind the Most Frequent Request IDs
Implement an algorithm to identify the top k most frequent request IDs from a stream of log events, breaking frequency ties by smaller ID values and handling cases where k exceeds the number of unique IDs.
Coding & AlgorithmsOnsitehash-tableheapsorting - AmazonMediumData ScientistFind top-spend categories per customer with ranking
This question evaluates proficiency with SQL aggregation and JOINs, analytic/window functions (RANK()), tie and NULL/edge-case handling, and percent-of-total calculations for per-customer spend analysis.
Data Manipulation (SQL/Python)Onsite - AmazonMediumSoftware EngineerFinding the Root Cause of an Intermittent Failure When the Obvious Metrics Look Healthy
A behavioral debugging question: describe a system that failed intermittently while its obvious metrics looked healthy, how you found the root cause, and how long it took. It tests whether you can explain why the dashboards stayed green and show a systematic, evidence-driven narrowing process.
Behavioral & LeadershipOnsite - AmazonMediumFrontend EngineerFormat a Forest of Nested Comments
This problem tests your ability to reconstruct hierarchical relationships from flat input data and format them into a visual tree representation with specific character-based connectors.
Coding & AlgorithmsOnsiteRecursionTree TraversalString Formatting - AmazonMediumApplied ScientistFrom Early NLP Embeddings to Modern LLM Embeddings
Evaluate the architectural and practical evolution of NLP text embeddings, and formulate a decision framework comparing small bi-encoders versus large LLM-based embedding models based on retrieval quality, latency, and operational cost.
Machine LearningOnsiteEmbeddingsNLPInformation Retrieval - AmazonMediumMachine Learning EngineerGRPO in NumPy: Group-Relative Advantages, Process Rewards and Shaped Rewards
Implement the core of Group Relative Policy Optimization in a NumPy notebook: group-normalized advantages, the clipped objective with a KL penalty, per-token credit from process rewards, and shaped rewards. Tests fluency with array axes and broadcasting and an understanding of how reward normalization interacts with shaping terms.
Machine LearningOnsite - AmazonMediumSoftware EngineerGenAI Literacy Questions: Daily AI Use, Handling Bad AI Output, and RAG Projects
Behavioral questions on generative AI literacy reported from hiring manager and Bar Raiser rounds: how you use AI tools day to day, a time you caught bad AI output, and a walkthrough of a retrieval-augmented generation project. It tests verification habits, judgment about data boundaries and RAG fundamentals.
Behavioral & LeadershipOnsite - AmazonMediumSoftware EngineerGeneralize Dictionary Merging
Explain an approach to merging two dictionaries and generalizing it efficiently to k dictionaries, explicitly identifying the collision semantics that must be clarified.
Software Engineering FundamentalsOnsite - AmazonMediumSoftware EngineerHigh Availability and Failover for a Primary-Replica Database
This problem tests your ability to design a resilient database architecture that minimizes downtime and data loss during node failures.
System DesignOnsiteDatabaseHigh AvailabilityReplication - AmazonMediumProduct ManagerHotel Keycard System Design
Practice a hotel keycard product and system design interview that covers guest experience, access control, offline validation, cryptographic credential handling, revocation, audit logs, integrations, security threats, and hotel operational failure modes.
Product / Decision MakingOnsite - AmazonMediumData ScientistIdentify First Daily Order for Each Merchant
This question evaluates proficiency in data manipulation with SQL and related tools, focusing on identifying the first transaction per merchant for each calendar date and handling ordering and deduplication within grouped transactional records.
Data Manipulation (SQL/Python)Onsite - AmazonMediumBusiness Intelligence EngineerIdentify Most Popular First-Watched Movie in Viewing History
This question evaluates proficiency in data manipulation and temporal event analysis, assessing competency in identifying per-user earliest views and aggregating frequencies using SQL or Python.
Data Manipulation (SQL/Python)Onsite - AmazonMediumData ScientistIdentify P-Value Limitations and Complementary Approaches
Identify P-Value Limitations and Complementary Approaches evaluates statistical assumptions, formulas, estimation strategy, uncertainty, edge cases, and interpretation in a realistic interview setting. A strong answer states assumptions, handles edge cases, explains trade-offs, and shows how to validate the result clearly.
Statistics & MathOnsite - AmazonMediumBusiness Intelligence EngineerIdentify Top-Buying Customers Daily with SQL Query
This question evaluates a candidate's competency in SQL data manipulation, including aggregation over calendar dates, grouping by customer, and handling ties when determining top buyers.
Data Manipulation (SQL/Python)Onsite - AmazonMediumBusiness Intelligence EngineerIdentify Unique Unordered City Pairs in Flight Log
This question evaluates competency in data manipulation, deduplication of symmetric relationships, and handling unordered pairs within relational or tabular datasets using SQL or Python/Pandas.
Data Manipulation (SQL/Python)Onsite - AmazonMediumBusiness Intelligence EngineerIllustrate SQL Join Results with Duplicate Keys
This question evaluates understanding of SQL join semantics and the effect of duplicate key values on result cardinality, assessing competency in relational data manipulation and reasoning about result sets.
Data Manipulation (SQL/Python)Onsite - AmazonMediumSoftware EngineerImplement Cache and Rotate Matrix
This two-part question evaluates competency in data structure design and in-place array manipulation, specifically the ability to implement an LRU cache with O(1)-average operations (including recency management, updates, and evictions) and to rotate an n x n matrix 90 degrees clockwise in place without extra space.
Coding & AlgorithmsOnsite - AmazonMediumApplied ScientistImplement K-means and solve interval/frequency tasks
This multi-part question evaluates understanding of K-means clustering, interval-merging algorithms, and frequency-based top-k retrieval, assessing competencies in unsupervised learning concepts, algorithmic problem solving, data structures, and complexity analysis.
Coding & AlgorithmsOnsite - AmazonMediumSoftware EngineerImplement LRU cache with O(1) ops
This interview question evaluates algorithm design, data structures, correctness, complexity, edge cases, and implementation details in a realistic interview setting. A strong answer for Implement LRU cache with O(1) ops states assumptions, handles edge cases, explains trade-offs, and shows how to validate the result clearly.
Coding & AlgorithmsOnsite - AmazonMediumApplied ScientistImplement Multi-Head Attention from Scratch in NumPy
This problem tests your understanding of Transformer components by requiring an implementation of Multi-Head Scaled Dot-Product Attention using only NumPy, emphasizing matrix manipulations and numerical stability.
Coding & AlgorithmsOnsiteTransformersNumPyAttention - AmazonMediumMachine Learning EngineerImplement Multi-Head Attention with a KV Cache and Cached Grouped-Query Attention
Implement causal multi-head attention from scratch, add a key-value cache for token-by-token decoding, and extend the forward pass to grouped-query attention, where several query heads share one key and value head. Tests tensor shape discipline, masking with cached positions, and reasoning about decode compute and cache memory.
Machine LearningOnsite
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