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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 1351–1380 of 5874 results
- Capital OneHardSoftware EngineerDesign a scalable banking system
This question evaluates system design skills focused on distributed systems architecture, transactional integrity, strong consistency models, security and authentication, external payment and ATM integrations, data modeling, API design, concurrency control, and operational monitoring for financial platforms.
System DesignOnsite - Capital OneMediumSoftware EngineerDesign a transaction class for deposits/withdrawals
This problem tests your ability to design a robust, thread-safe class for managing bank account transactions, focusing on atomicity and data consistency.
Software Engineering FundamentalsTechnical ScreenConcurrencyObject-Oriented DesignThread-Safety - Capital OneMediumSoftware EngineerDesign an Enterprise Agent Platform with Guardrails and Latency Control
Design an enterprise agent platform with durable execution, deliberate workflow-versus-agent choices, enforceable tool guardrails, and a dependency-aware latency plan.
System DesignOnsite - Capital OneMediumSoftware EngineerFind Repeated-Value Patterns in a Matrix
Match a symbol pattern inside an integer matrix using per-window bijections, repeated values, distinct symbols, and ordered match coordinates.
Coding & AlgorithmsOnline Assessment - Capital OneMediumSoftware EngineerFind the First Array Element Smaller Than Both of Its Neighbors
A coding problem that asks for the first element of an integer array whose left and right neighbors are both strictly larger than it, returning -1 when no element qualifies. It tests careful boundary handling, strict comparisons when neighbors are equal, and precise output rules.
Coding & AlgorithmsOnline Assessment - Capital OneMediumSoftware EngineerFind the Row Watched by the Most Security Cameras
Each security camera covers a symmetric band of rows around its mounted position; find the integer row watched by the most cameras, breaking ties toward the smallest row number, using a sweep-line count instead of scanning every covered row.
Coding & AlgorithmsOnline Assessmentsweep-linesortingintervals - Capital OneMediumSoftware EngineerFind the Top-Left Submatrix Matching a Grid Pattern With Letter Variables
Locate a pattern grid inside an integer matrix, where each pattern cell is either an exact number or a letter that must stand for one consistent value, and return the top-left corner of the match with the lowest row and then the lowest column. It tests two-dimensional scanning, variable binding, and tie-breaking rules.
Coding & AlgorithmsOnline Assessment - Capital OneMediumSoftware EngineerGrid State After a Given Number of Days of Spoilage Spreading to Neighbors
A grid holds empty cells, fresh items and spoiled items, and each day spoilage spreads from every spoiled item to its edge-adjacent fresh neighbors. Given the grid and a number of days that may be very large, return the grid after exactly that many days. It tests simultaneous multi-source spreading, day-by-day timing, and unreachable cells.
Coding & AlgorithmsHR Screen - Capital OneMediumSoftware EngineerImplement 2D transforms and find max-lit point
This question evaluates array-manipulation and interval-analysis skills, specifically in-place 2D matrix transformations (row/column swaps, reversals, rotations) and determining the point with maximum overlap among one-dimensional illumination intervals.
Coding & AlgorithmsOnline Assessment - Capital OneMediumSoftware EngineerImplement deposit, withdraw, and transfer in a class
This question evaluates a candidate's competence in concurrent programming, atomic state updates, and class-level account management for basic monetary operations.
Coding & AlgorithmsOnsite - Capital OneMediumSoftware EngineerIn-Memory Banking System: Deposits, Transfers, Top-N Activity, Test Harness
An object-oriented coding exercise that builds an in-memory banking system in stages: creating accounts and deposits, transfers between accounts, and ranking the top N accounts by activity. It also tests writing a harness that runs string-array test commands, and confirming whether activity means operation count or amount moved.
Software Engineering FundamentalsTechnical Screen - Capital OneMediumSoftware EngineerMake the Case for a Banking Virtual Assistant: Who Wins and How?
Argue what an in-app virtual assistant would deliver to a retail bank and to its account holders, backing each claim with a mechanism, a metric and the money-specific risks that offset it.
Product Design & StrategyOnsiteproduct-sensefintechchatbots - Capital OneMediumSoftware EngineerMake the Case for a Customer-Facing Insurance Claims Chatbot
A case-study opener: argue what benefits a customer-facing chatbot would bring to an insurer and to its policyholders. Tests whether you anchor each benefit to a concrete mechanism and metric, and weigh it against the specific risks of giving automated answers about claims and money.
Product Design & StrategyOnsiteproduct-sensecase-studyrisk-tradeoffs - Capital OneMediumSoftware EngineerMerchant-Locked Payment Codes: Trade-offs and a Buggy Checker
A three-part fintech case on merchant-locked, single-merchant payment codes: discuss their trade-offs for cardholder and issuer, hand-validate sample codes against a digit-position rule table, then find and fix three planted bugs in a flawed validator.
Software Engineering FundamentalsTechnical Screencase-interviewdebuggingvalidation-logic - Capital OneMediumSoftware EngineerNew-Grad Behavioral Round: Teamwork, Conflict, and a Failure
A new-grad onsite behavioral round asking for three separate stories from your own project work: one on teamwork, one on a disagreement with someone else, and one on a real failure. Tests whether you can tell a specific, honest story with your own contribution clearly visible, rather than a generic or deflected answer.
Behavioral & LeadershipOnsitebehavioralstar-methodnew-grad - Capital OneMediumSoftware EngineerPlace Pieces on a Grid
This question evaluates spatial reasoning, matrix and array manipulation, collision detection, and stateful simulation skills required to implement ordered placement of shaped pieces on a grid.
Coding & AlgorithmsOnsite - Capital OneMediumSoftware EngineerPrepaid Travel Card Case Study: Checks, Trade-offs, Buggy Filter
A three-part case study on prepaid travel cards: weigh the trade-offs of issuing them, manually check sample numbers against length, Luhn, and prefix rules, then debug Python filter code whose conditionals let invalid numbers through. Tests product reasoning, careful manual rule-checking, and evidence-driven debugging.
Software Engineering FundamentalsOnsitecase-studyvalidationdebugging - Capital OneMediumSoftware EngineerProject Stories on Teamwork, Conflict and Failure for a New-Grad Behavioral Round
A new-grad behavioral round built on stories from your own projects, covering teamwork, a conflict with a teammate or stakeholder, and a failure, each told in Situation, Task, Action, Result form. It tests personal ownership, how you handle disagreement and whether you learn from your mistakes.
Behavioral & LeadershipOnsite - Capital OneMediumSoftware EngineerReason About and Validate Virtual Card Transactions
Implement a policy validation engine for encoded virtual card numbers against incoming transactions, handling rule parsing, Luhn checksum verification, and structured status reporting.
Software Engineering FundamentalsOnsiteStringsValidationClean Code - Capital OneMediumSoftware EngineerRemove nodes with a given value
This problem tests your ability to manipulate singly linked lists, specifically handling edge cases like removing head nodes and reassigning pointers in a single pass.
Coding & AlgorithmsTechnical ScreenLinked ListPointersRecursion - Capital OneHardSoftware EngineerReorder a String by Alternating Its Front and Back Characters
Rearrange a string by taking characters alternately from its front and its back: first, last, second, second-to-last and so on until every character is used once. Tests clean index handling for even and odd lengths and building the result efficiently for long inputs.
Coding & AlgorithmsOnline Assessment - Capital OneMediumSoftware EngineerReorder a String by Alternating Its Left and Right Ends
This problem tests string manipulation, two-pointer logic, and the ability to efficiently manage index traversal in both directions simultaneously.
Coding & AlgorithmsOnline AssessmentTwo PointersStringsAlgorithms - Capital OneMediumSoftware EngineerResolve Conflict and Set a Team Objective
Tests your ability to resolve technical and interpersonal disagreements constructively and establish measurable, value-driven team objectives.
Behavioral & LeadershipOnsiteBehavioralConflict ResolutionLeadership - Capital OneMediumSoftware EngineerReturn the Top Two Teams by Points, Goal Difference, and Tie Breakers
Implement a ranking algorithm to evaluate sports competition matches, compute points, goal differential, and total goals for each team, and return the indices of the top two teams using multi-level tie-breakers.
Coding & AlgorithmsOnline AssessmentSortingHash TableArray - Capital OneMediumSoftware EngineerSimulate Rot Spreading Through an Orchard Grid Over a Number of Days
A grid simulation question about an orchard of rotten trees, healthy trees and empty ground, where each day rot spreads at once from every rotten tree to the healthy trees directly beside it. It asks for the orchard after a given number of days and tests simultaneous updates, blocked cells and very large day counts.
Coding & AlgorithmsOnline Assessment - 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 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
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