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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 2191–2220 of 9403 results
- Capital OneMediumSoftware EngineerSimulate a Bank Ledger With Validated Transfers, Deposits and Withdrawals
A coding exercise that simulates a bank's in-memory ledger: apply an ordered sequence of transfers, deposits and withdrawals across numbered accounts and report which requests succeed. It tests careful validation of account numbers and balances, ordered state updates, and 64-bit arithmetic.
Coding & AlgorithmsOther - Capital OneMediumMachine Learning EngineerSimulate round-robin package assignment to servers
This problem tests array indexing manipulation and logic for stateful resource allocation, specifically handling circular queues with dynamic availability constraints.
Coding & AlgorithmsOnline AssessmentArraysSimulationQueueing - Capital OneMediumData ScientistSketch function from derivatives and limits
This question evaluates understanding of calculus concepts—derivatives, concavity, limits, and continuity—and the ability to interpret derivative sign patterns to infer monotonicity and locate extrema.
Statistics & MathTechnical Screen - Capital OneMediumMachine Learning EngineerSolve Four Coding Assessment Tasks
This multi-part coding question evaluates array manipulation, algorithm simulation, deterministic spatial placement, and constrained optimization competencies across tasks involving cumulative thresholds, iterative subtraction sequences, fixed-shape grid placement, and minimal-increment adjustments for monotonic patterns.
Coding & AlgorithmsOnline Assessment - Capital OneEasyMachine Learning EngineerSolve OA tasks on string, grid path, subarrays
This problem tests proficiency in string manipulation, grid traversal with condition-based movement, and linear-time subarray analysis.
Coding & AlgorithmsOnline AssessmentArraysDynamic ProgrammingGrid Traversal - Capital OneMediumSoftware EngineerSolve four algorithmic coding tasks
This multi-part question evaluates algorithmic problem-solving across frequency counting (equal-value pairs), simulation and in-place grid transformation (match-three gravity), matrix diagonal pattern checking, and interval/range data-structure management, emphasizing correctness under constraints and rigorous time/space complexity reasoning.
Coding & AlgorithmsOnline Assessment - Capital OneHardSoftware EngineerSolve multiple algorithmic interview questions
This multi-part prompt evaluates algorithmic problem-solving and core data-structure competencies such as array manipulation, modular/date arithmetic, matrix transformations, dynamic set and interval maintenance, string concatenation frequency counting, and path-based expression evaluation on grids.
Coding & AlgorithmsOnline Assessment - Capital OneMediumSoftware EngineerSort Each Adjacent Pair of an Array, Leaving an Odd Last Element in Place
Given an integer array, put each consecutive pair of elements in ascending order while keeping every pair in its original place, and leave the final element untouched when the length is odd. Tests precise reading of a short specification and careful index handling.
Coding & AlgorithmsOnline Assessment - Capital OneMediumSoftware EngineerSort Every Concentric Matrix Border Clockwise
This problem tests array traversal, boundary management, and sorting logic by requiring you to isolate concentric layers of a matrix and sort their contents independently.
Coding & AlgorithmsOnline AssessmentArraysSortingMatrix - Capital OneMediumSoftware EngineerSort Matrix Diagonals By Their Values
Tests matrix traversal along anti-diagonals, string formation, and custom multi-key sorting with deterministic tie-breaking.
Coding & AlgorithmsTechnical Screenmatrixsortingstrings - Capital OneMediumSoftware EngineerSorted Sums of Absolute Differences Over All Cyclic Shifts of an Array
Given two integer arrays of equal length, compute the sum of absolute differences between the second array and every cyclic rotation of the first, then return all of these sums in non-descending order. It tests rotation index arithmetic, accumulation over every shift, and exact output ordering.
Coding & AlgorithmsOnline Assessment - Capital OneHardSoftware EngineerSum of Distinct Values on the Borders of All Maximum-Sum Square Frames
Among all square frames of a given size inside an integer matrix, find those with the largest border sum, then add up the distinct values that appear on the borders of every such frame. Tests careful border enumeration that excludes interior cells, tie handling across several frames, and de-duplication by value.
Coding & AlgorithmsOnline Assessment - Capital OneHardMachine Learning EngineerSupport updates and count target-sum pairs
This problem tests the ability to maintain frequency counts of elements in a dynamic dataset and perform efficient range-sum queries for pairs that satisfy a target condition.
Coding & AlgorithmsOnline AssessmentHash MapData StructuresFrequency Array - Capital OneMediumData ScientistTest and Run a Reproducible Data Science Pipeline
Design and implement a robust, testable Python data pipeline class that validates input data schemas, handles feature transformation, logs execution metrics, and produces versioned outputs. Write targeted unit and integration tests ensuring graceful failure on corrupted inputs.
Software Engineering FundamentalsTechnical ScreenPythonData PipelinesTesting - Capital OneMediumSoftware EngineerTop Two Teams by Points, Then Goal Difference, Then Goals Scored
Given parallel arrays of wins, draws, goals scored and goals conceded for each team, compute points as three per win plus one per draw and return the indices of the top two teams. Ties are broken by goal difference, then goals scored, then index, testing multi-key comparison and careful tie handling.
Coding & AlgorithmsHR Screen - Capital OneHardData ScientistUse data to resolve an ambiguous problem
This question evaluates a data scientist's competency in end-to-end data analysis, causal identification, statistical modeling, data quality and governance, bias assessment, and communication of uncertainty when addressing an ambiguous business problem.
Behavioral & LeadershipTechnical Screen - Capital OneMediumData ScientistValidate Unit-Test Coverage and Identify Missing Scenarios
This interview question evaluates algorithm design, data structures, correctness, complexity, edge cases, and implementation details in a realistic interview setting. A strong answer for Validate Unit-Test Coverage and Identify Missing Scenarios states assumptions, handles edge cases, explains trade-offs, and shows how to validate the result clearly.
Coding & AlgorithmsOnsite - Capital OneMediumMachine Learning EngineerValidate virtual credit card transactions from encoded IDs
This question evaluates understanding of virtual credit card product trade-offs and the ability to design data models and deterministic validation logic for encoded transaction attributes, testing competencies in payment systems, data encoding/decoding, and rule-based validation.
System DesignOnsite - Capital OneMediumSoftware EngineerVirtual Card Case Study: Trade-offs, Card Number Rule Checks, and Debugging a Filter
A three-part virtual credit card case study: weigh the benefits and costs of giving merchants virtual card numbers, check five sample numbers against length, Luhn checksum and prefix rules, and debug a Python filter whose conditionals accept invalid numbers. It tests product reasoning, careful manual analysis and evidence-driven debugging.
Software Engineering FundamentalsOnsite - Capital OneMediumSoftware EngineerVirtual Card Numbers Case: Trade-offs, Payment Validation Rules, Debugging
A three-stage case interview on virtual credit card numbers. It covers the benefits and problems of virtual cards for cardholders and the issuer, a hand walkthrough that validates payments against digit-by-digit card number rules, and debugging messy validator code for inverted boolean operators and boundary errors.
Software Engineering FundamentalsTechnical Screen - Capital OneEasyData ScientistVisualize Price Impact on Demand and Profit Trends
Evaluates price sensitivity and profit-curve reasoning for a network service with downward-sloping demand. Strong answers explain demand curves, profit shape, marginal revenue, marginal cost, and optimal price.
Analytics & ExperimentationOnsite - Capital OneMediumData ScientistWhy Retain Phone Channel Despite Lower Profitability?
This interview question evaluates behavioral evidence, ownership, communication, trade-offs, and measurable outcomes in a realistic interview setting. A strong answer for Why Retain Phone Channel Despite Lower Profitability? states assumptions, handles edge cases, explains trade-offs, and shows how to validate the result clearly.
Behavioral & LeadershipTechnical Screen - Capital OneMediumData ScientistWrite SQL for lowest price with ratings
This question evaluates SQL data-manipulation skills including aggregation, conditional filtering, NULL handling, grouping, and deterministic ordering, and sits in the Data Manipulation (SQL/Python) domain with an emphasis on practical application of query writing rather than purely conceptual design.
Data Manipulation (SQL/Python)Technical Screen - Capital OneMediumData ScientistWrite SQL for theme-park revenue and visits
This question evaluates SQL data-manipulation and analytical skills, including joins, aggregations, date-range filtering, handling multiple ticket ownership, and edge cases like zero counts when computing revenue and visit metrics.
Data Manipulation (SQL/Python)Onsite - Capital OneMediumData ScientistWrite SQL to compute campaign net revenue
This question evaluates SQL-based data manipulation and analytics skills, including aggregation, deduplication, date-range filtering, revenue and cost calculations, and selection logic for prioritizing additional donors.
Data Manipulation (SQL/Python)Onsite - Capital OneMediumData ScientistWrite SQL to find top net-revenue products
This question evaluates proficiency in SQL data manipulation, including joins, aggregations, date-window filtering, handling returns and net-revenue calculations, plus the use of analytic/window functions for per-category ranking and tie-breaking.
Data Manipulation (SQL/Python)Technical Screen - CargurusMediumData ScientistAssess a Distribution and Derive Coin-Toss Expectations
This problem tests the ability to distinguish between Bernoulli and Binomial processes, calculate expected values and variances, and validate model assumptions based on observed sample data.
Statistics & MathTechnical ScreenProbabilityStatisticsMLE - CargurusMediumData ScientistReverse a Character Array In Place
This problem tests the ability to manipulate array elements in-place using two-pointer logic while adhering to strict space complexity constraints.
Coding & AlgorithmsTechnical ScreenArraysTwo PointersIn-place - CarvanaEasySoftware EngineerAnswer Cross-Functional Workplace Prompts
This question evaluates communication, conflict-resolution, cross-functional collaboration, and the candidate's ability to explain technical concepts to non-technical stakeholders, along with practical familiarity with using AI tools in engineering workflows.
Behavioral & LeadershipOnsite - CarvanaEasySoftware EngineerDesign an Attendance Payroll Service
This question evaluates system design and backend engineering skills, including API design, data modeling for time-series attendance, payroll computation logic, consistency guarantees, integration/synchronization with external sources, and strategies for handling high-volume, bursty traffic.
System DesignOnsite
Capital One