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Software Engineer 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 1321–1350 of 5874 results
- C3 AIEasySoftware EngineerDesign a restaurant reservation system
This question evaluates skills in system architecture and engineering, including data modeling, API design, concurrency control to prevent double-booking, availability and scheduling logic, scalability under traffic spikes, and operational concerns like auditability and low-latency queries.
System DesignOnsite - C3 AIMediumSoftware EngineerEvaluate Factual Accuracy and Consistency in a Domain-Specific RAG Chatbot
Evaluate a rare-disease RAG chatbot using domain consistency and expert review, and distinguish factual accuracy from retrieval metrics and lexical overlap.
Machine LearningOnline Assessment - C3 AIMediumSoftware EngineerMaximum-Sum Star with at Most K Arms
Find the maximum node-value sum of a graph star with at most k arms, allowing a center alone and avoiding harmful negative-value leaves.
Coding & AlgorithmsOnline Assessment - Candid HealthEasySoftware EngineerImplement a Callback Signaling Registry with Register, Unregister and Signal
Implement a minimal in-process signaling system with register_callback, unregister_callback and signal functions that all return None. Tests requirement clarification, callback storage and hashability, execution order, isolation of failing callbacks, and prevention of reentrant signal loops.
Software Engineering FundamentalsTechnical Screen - Capital OneMediumSoftware EngineerAnalyze and Debug Virtual-Card Payment Rules
Implement and debug a rule-validation engine for virtual card authorization that accurately parses currency strings into integer cents and evaluates spending boundaries and merchant restrictions.
Software Engineering FundamentalsOnsitePythonData ParsingBoundary Conditions - Capital OneMediumSoftware EngineerAnswer learning and challenge behavioral prompts
This question evaluates learning agility, problem-solving, influence, and leadership competencies by probing quick learning, process-challenging, and trade-off management in real work scenarios.
Behavioral & LeadershipTechnical Screen - Capital OneMediumSoftware EngineerAnswer motivation and teamwork questions
The question evaluates motivation, cultural fit, communication, teamwork, conflict-resolution, and the ability to describe concrete impact from collaborative work.
Behavioral & LeadershipTechnical Screen - Capital OneMediumSoftware EngineerApply commands to transform a matrix
This question evaluates array and matrix manipulation skills, specifically in-place row reversal, row swapping, and 90-degree rotation, and falls under the Coding & Algorithms domain with emphasis on practical implementation.
Coding & AlgorithmsOnline Assessment - Capital OneMediumSoftware EngineerBehavioral: Using AI Tools in Daily Engineering Work and to Improve Efficiency
A behavioral interview question for software engineers about AI tools: how you use them in day-to-day engineering work, and a specific example of how they improved your efficiency. It tests concrete examples, how AI output is verified, judgment about confidential code and data, and honest, measured results.
Behavioral & LeadershipTechnical Screen - Capital OneMediumSoftware EngineerBenefits of a Customer-Facing Chatbot for a Bank and Its Customers
A case-study opener asking what benefits a customer-facing chatbot would bring to a bank and to its customers. It tests whether you can tie each benefit to a concrete mechanism and metric, and weigh it against risks specific to banking such as wrong answers about money, authentication and privacy.
Product Design & StrategyOnsite - Capital OneMediumSoftware EngineerBlock-Building Operations: Check Whether a Free Segment Starts at a Position
Process operations on a number line that either place a block at a position or ask whether a segment of a given length starting at a position is free of blocks, and return the answers as a string of ones and zeros. It tests handling interleaved updates and range checks efficiently over large coordinates.
Coding & AlgorithmsOnline Assessment - Capital OneMediumSoftware EngineerBuild a Banking System with Activity Rankings
This problem tests your ability to design a system that maintains account state and dynamically updates an ordered leaderboard of account activity using efficient data structures.
Coding & AlgorithmsOnsiteHash MapBalanced BSTDesign - Capital OneMediumSoftware EngineerBurner Card Numbers: Trade-offs, Hand Checks and a Buggy Validator
A three-part fintech case: weigh the trade-offs of disposable card numbers, check sample numbers by hand against format, Luhn and issuer-range rules, then find three bugs in a filter that rejects valid numbers and accepts invalid ones.
Software Engineering FundamentalsOnsitedebuggingluhnproduct-sense - Capital OneMediumSoftware EngineerCard Issuer Backend: Fast Purchase Approvals and a Secure PII Vault
Design the issuer-side platform that approves or declines card purchases in tens of milliseconds, settles them later, and stores cardholder identity data so a breach of any one service exposes as little as possible.
System DesignTechnical Screensystem-designpaymentslatency - Capital OneMediumSoftware EngineerCheck Alternating Highs and Lows Around a Circular Array
Check strict high-low alternation around a circular array, including equal neighbors, wraparound comparisons, and the two-element case.
Coding & AlgorithmsOnline Assessment - Capital OneMediumSoftware EngineerCount Numbers With Odd Zeros
This question evaluates proficiency in numeric digit analysis and parity-based counting, testing the competency to reason about decimal representations of integers within the Coding & Algorithms domain at a practical application level. It is commonly asked to assess basic algorithmic thinking, efficient iteration and counting skills, and careful handling of edge cases in technical interviews.
Coding & AlgorithmsTechnical Screen - Capital OneMediumSoftware EngineerCount Pairs of Cyclically Equivalent Integers
This problem tests your ability to normalize strings under cyclic rotation using hashing or canonical representation, combined with frequency counting to efficiently identify equivalent pairs.
Coding & AlgorithmsOnline AssessmentHashingStringsCombinatorics - Capital OneMediumSoftware EngineerCount Pairs of Points Within 2 Units on Both Axes
A coding question that asks how many pairs of points intersect, where two points intersect when both their x-coordinates and their y-coordinates differ by at most 2. It tests counting unordered pairs with duplicate points, inclusive bounds and scaling to 100,000 points with large coordinates.
Coding & AlgorithmsOnline Assessment - Capital OneHardSoftware EngineerCount Subarrays Containing at Least k Disjoint Pairs of Equal Values
Count the contiguous segments of an integer array, framed as fruit types on a conveyor belt, that contain at least k pairs of equal values with no position used in two pairs. Tests reasoning about how the number of disjoint pairs changes as a segment grows, and efficient counting on inputs of up to 100,000 elements.
Coding & AlgorithmsOnline Assessment - Capital OneMediumSoftware EngineerCount Subarrays Whose Step-by-Step Changes Match an Up, Flat, Down Pattern
Count the fixed-length windows of an integer array whose consecutive rises, equal steps, and drops follow a given pattern of 1, 0, and -1 values, counting overlapping matches separately. Tests turning a comparison rule into an exact window check with correct index bounds.
Coding & AlgorithmsOnline Assessment - Capital OneMediumSoftware EngineerCount Three-Digit Numbers With All-Distinct Digits in a Range
A coding question that asks you to count the three-digit integers in an inclusive range whose hundreds, tens and units digits are all different from one another. It tests digit extraction, inclusive range boundaries and treating zero digits like any other digit.
Coding & AlgorithmsOnline Assessment - Capital OneMediumSoftware EngineerCount Windows That Follow an Increase, Equal, Decrease Pattern
A coding question that gives an integer array and a pattern of 1, 0 and -1 values standing for an increase, an equal step and a decrease, and asks how many windows of consecutive elements follow the pattern exactly. It tests translating pairwise comparisons into steps and counting overlapping matches efficiently.
Coding & AlgorithmsOnline Assessment - Capital OneMediumSoftware EngineerCount ordered pairs that concatenate to target
This question evaluates a candidate's ability to manipulate string and numeric representations, perform efficient counting, and leverage associative data structures to identify matching concatenations.
Coding & AlgorithmsOnline Assessment - Capital OneMediumSoftware EngineerDescribe leadership challenges and managing a difficult report
This question evaluates leadership, conflict-resolution, and team-management competencies in a software engineering context by probing examples of leading projects and managing a difficult or noncompliant direct report, and is categorized under Behavioral & Leadership.
Behavioral & LeadershipOnsite - Capital OneMediumSoftware EngineerDesign Nearest-Pickup Search with Time
Design efficient nearest-pickup search for latitude-longitude data and a time-aware extension while clarifying distance, ties, result order, and temporal ranking.
Software Engineering FundamentalsOnline Assessment - Capital OneMediumSoftware EngineerDesign a Banking Component with Transfers and Activity Rankings
Design an in-memory banking service supporting account creation, deposits, atomic transfers, and activity rankings driven by a string-based command interface.
Software Engineering FundamentalsOnsiteDesignHash TableSorting - Capital OneMediumSoftware EngineerDesign a Buy-Now-Pay-Later Checkout Backend: Latency and PII Storage
Design the backend of a buy-now-pay-later checkout financing service that approves or declines a purchase in real time against a shopper's revolving credit line, then go deep on latency budgeting for the decision and on securely storing borrowers' personal data.
System DesignTechnical Screensystem-designfintechconcurrency - Capital OneMediumSoftware EngineerDesign a Credit Card System: Authorization Latency and Sensitive Data Storage
A system design question that asks for the backend of a credit card system, then goes deep on what payment authorization latency is reasonable and how to achieve it, and on how to store cardholders' sensitive personal information. It tests transaction flow design, available-credit concurrency, latency budgeting, and data protection.
System DesignTechnical Screen - Capital OneMediumSoftware EngineerDesign a Credit Card System: Authorization, Fraud, Bureau Reports, Limit Increases
A system design question for a credit card platform covering customer login, real-time payment authorization with fraud checks, monthly credit bureau reporting, a spending overview, and instant credit limit increase decisions. It tests laying out entities, services and read and write paths before choosing deep dives.
System DesignTechnical Screen - Capital OneMediumSoftware EngineerDesign a highly reliable account balance system
This question evaluates a candidate's ability to architect a highly reliable transactional account-balance service, testing competencies in data modeling and storage choice, API design for idempotency, concurrency and consistency mechanisms, replication/failover, partitioning for scale, and auditability.
System DesignOnsite
C3 AI
Capital One