practice a little every day, paws crossed ♡
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
- Companies
- 11
- Topics
- 8
- Languages
Showing 3421–3450 of 4616 results
- Retell AIMediumSoftware EngineerDesign a Smooth Per-Customer Calls-Per-Second Controller
Design a distributed outbound call pacing service that enforces smooth per-tenant calls-per-second (CPS) rate limits while ensuring durable queueing, priority scheduling, and safe failover.
System DesignTechnical ScreenRate LimitingDistributed SystemsTask Scheduling - Retell AIHardSoftware EngineerDesign and Implement a Mini SQL Query Engine
This question evaluates a candidate's ability to design and build a small SQL query engine, covering tokenization, parsing, and query execution over in-memory tables. It tests system design and compiler-style thinking, including how to scope a large problem into an extensible v1 and reason about extending it with sorting, aggregation, and joins. This is a system design and practical implementation question assessing both architectural judgment and coding ability.
System DesignTechnical Screen - Retell AIEasySoftware EngineerEvaluate a Small Stack-Based Integer Language
Implement an interpreter for a stack-based integer language supporting arithmetic, stack manipulation, output, and immediate error reporting with partial output preservation.
Coding & AlgorithmsTechnical Screenstackparsingsimulation - Retell AIMediumSoftware EngineerQuery an Indexed In-Memory Numeric Table
This problem tests the ability to implement efficient multi-column indexing using binary search and sorted set intersections to handle complex range queries.
Coding & AlgorithmsTechnical ScreenData StructuresBinary SearchIndexing - RetoolMediumSoftware EngineerCompute max profit with forced trades
Compute max profit with forced trades 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 & AlgorithmsTechnical Screen - RetoolHardSoftware EngineerDesign car rental schema and APIs
This question evaluates data modeling, transactional integrity, concurrency control, REST API and workflow design, and system scalability within the car rental domain in the System Design category.
System DesignTechnical Screen - ReutersEasySoftware EngineerDiscuss overfitting, contrastive learning, transformers
This question evaluates understanding of supervised learning generalization (overfitting and underfitting), contrastive representation learning and contrastive loss functions, and transformer architectures, assessing core competencies in model evaluation, representation learning, and neural architecture concepts within the Machine Learning domain.
Machine LearningTechnical Screen - RevolutHardData AnalystDefine Ultra success and detect suspicious transactions
This question evaluates a candidate's skills in product analytics, cohort and retention measurement, SQL-based metric design and segmentation, and rule-based fraud detection using transactional and activity data.
Analytics & ExperimentationTechnical Screen - RevolutEasyData ScientistDefine Ultra success metrics and detect suspicious transactions
This question evaluates a data scientist's ability to define primary, diagnostic, and guardrail metrics for a product launch and to design rule-based suspicious-transaction detection using available schema, emphasizing metric definition, defensible proxy selection, SQL-based data modeling, and financial-crime domain knowledge.
Analytics & ExperimentationTechnical Screen - RevolutMediumSoftware EngineerDesign multi-region banking data synchronization
This question evaluates competency in distributed systems and data consistency for financial applications, emphasizing replication, transaction correctness, conflict resolution, idempotency, and operational resilience.
System DesignTechnical Screen - RevolutMediumSoftware EngineerExplain DB concurrency, debugging slowness, DDD and CQRS
This question evaluates understanding of database concurrency control and isolation anomalies, backend performance investigation and diagnostic skills, and knowledge of architectural concepts DDD and CQRS, testing competencies in transaction semantics, operational troubleshooting signals, and architectural trade-offs.
Software Engineering FundamentalsTechnical Screen - RevolutMediumSoftware EngineerImplement a random fixed-size load balancer
This question evaluates understanding of randomized selection, efficient in-memory data structures, and API/state management for a fixed-capacity load balancer that must support addNode, removeNode, and uniform random routing while handling duplicates, removals, and empty-state behavior.
Coding & AlgorithmsTechnical Screen - RevolutMediumSoftware EngineerImplement a thread-safe money transfer
This question evaluates a candidate's mastery of concurrent programming and data-integrity principles, focusing on thread safety, atomic state updates, and deadlock avoidance when transferring funds between shared accounts.
Coding & AlgorithmsTechnical Screen - RilletMediumBackend EngineerDistribute Annual Revenue Across Twelve Months
This problem tests logic, integer arithmetic, and edge-case handling by requiring the distribution of a total sum into equal parts while managing remainders without using floating-point numbers.
Coding & AlgorithmsTechnical ScreenAlgorithmsInteger ArithmeticData Manipulation - RiotgamesEasySoftware EngineerAdmit and Recover from a Public Mistake
This question assesses the candidate's professional integrity, emotional intelligence, and ability to prioritize organizational impact over personal ego when a technical error occurs.
Behavioral & LeadershipTechnical ScreenOwnershipCommunicationCrisis Management - RiotgamesEasySoftware EngineerAggregate Letter-Number Groups
This problem tests string parsing, data aggregation using a hash map, and sorting techniques.
Coding & AlgorithmsTechnical ScreenStringsHash MapsSorting - RiotgamesEasySoftware EngineerChoose Between For and While Loops
This question evaluates your conceptual understanding of control flow structures, specifically focusing on readability, maintainability, and error prevention in loop selection.
Software Engineering FundamentalsTechnical ScreenControl FlowBest PracticesCode Quality - RiotgamesEasySoftware EngineerDescribe a Difficult Project
This question assesses the candidate's ability to navigate complex technical challenges, demonstrate ownership, and communicate their decision-making process within a team environment.
Behavioral & LeadershipTechnical ScreenBehavioralLeadershipCommunication - RiotgamesEasySoftware EngineerExplain JavaScript Numeric Edge Cases
This question tests your understanding of IEEE 754 floating-point representation in JavaScript, specifically how the language handles non-numeric values, precision limits, and type safety.
Software Engineering FundamentalsTechnical ScreenJavaScriptIEEE-754Data-Types - RiotgamesEasySoftware EngineerResolve a Disagreement Constructively
This question assesses the candidate's ability to navigate professional conflict through data-driven reasoning, collaborative communication, and focus on team objectives rather than personal ego.
Behavioral & LeadershipTechnical ScreenCommunicationConflict ResolutionCollaboration - RiotgamesEasySoftware EngineerTrace a Web Page Load Through the Browser
Tests an end-to-end understanding of how browsers fetch, parse, and render web pages, spanning low-level networking, DOM/CSSOM creation, script execution, and GPU-driven rendering pipelines.
Software Engineering FundamentalsTechnical ScreenBrowsersNetworkingWeb Performance - RippleHardSoftware EngineerFind path between two nodes in a binary tree
This question evaluates understanding of tree data structures, traversal and path reconstruction techniques, including reasoning about lowest common ancestors, ancestor–descendant relationships, duplicate identification, and handling absent targets.
Coding & AlgorithmsTechnical Screen - RipplingHardSoftware EngineerBill Deliveries with Historical Rates and Deferred Rounding
Bill deliveries with start-time historical rates, duplicate suppression, overlapping jobs, exact sub-cent accumulation, and configurable final half-up or half-even rounding.
Coding & AlgorithmsTechnical Screen - RipplingMediumSoftware EngineerBuild an E-Bike Rental Billing Dashboard With Rate Changes Over Time
Design a billing dashboard for a bike-share fleet that prices each ride at the per-minute rate in effect when it started, supports rate changes that take effect at a future timestamp without repricing past rides, and reports an exact running total as a formatted string.
Software Engineering FundamentalsTechnical Screenoop-designbillingidempotency - RipplingEasySoftware EngineerBuild an Expense Policy Rule Engine
This question tests your ability to design a rule evaluation engine that processes structured expense data against a set of logical conditions, including support for basic operators.
Coding & AlgorithmsTechnical ScreenAlgorithmsData-ModelingRule-Engine - RipplingEasySoftware EngineerClarify and Find Common Ancestors in a Graph
Reason about graph common ancestors by clarifying edge direction, DAG versus tree structure, self-ancestry, output semantics, and reachability algorithms.
Software Engineering FundamentalsTechnical Screen - RipplingEasySoftware EngineerClarify and Solve Currency Conversion Queries with a Maximum-Amount Follow-up
Analyze currency conversion queries and the reported maximum-amount backtracking follow-up without inventing missing rate or path rules. The solution shows how direction, precision, path consistency, same-currency behavior, and profitable cycles determine the graph algorithm and whether a finite answer exists.
Software Engineering FundamentalsTechnical Screen - RipplingMediumSoftware EngineerCompare Complete and Partial Poker Hands
Implement a poker hand evaluator that determines whether an incomplete poker hand can be completed from the remaining deck to beat an opponent's complete five-card hand.
Coding & AlgorithmsTechnical Screencombinatoricssearchgame-theory - RipplingMediumSoftware EngineerCompare Two Five-Card Numeric Hands
Compare two five-digit numeric hands under a nonstandard multiplicity ranking and original-position right-to-left tie-break, using extensible category evaluators rather than standard poker rules.
Coding & AlgorithmsTechnical Screen - RipplingMediumSoftware EngineerCompute concurrent online drivers
This question evaluates proficiency in algorithms and temporal data handling, including the use of efficient search techniques and complexity reasoning to count distinct active drivers over a sliding 24-hour window.
Coding & AlgorithmsTechnical Screen
Retell AI
Revolut
Rippling