Capital One logo

Capital One Interview Question Bank

Capital One's engineering loop is unusually predictable: a long CodeSignal OA gates everyone, then a single Power Day stitches four 45-60 minute rounds — coding, system design, case study, and behavioral — back to back. The technical bar is moderate but the case study and BQ rounds carry real weight, especially for MLE / Applied Research / Data Science where the business-context framing of a model decision is the differentiating signal.

More
63
Before you start
Showing 41 of 41
Other·60 min
MediumFree preview

Virtual Credit Card Validator (Case Study)

The canonical Capital One case study. Three phases: discuss virtual credit cards as a product, implement a rule-based transaction validator using bit-position rules embedded in card and transaction IDs, then debug provided code that fails some tests. Appears in SDE, MLE, and Applied Research loops.

SWE
MLE
RS
payment
object-design
debugging
critical-thinking
+2
Last asked 2026-07-136 related discussions

OJ Problems

practice in the online judge
63 total
Sort Every Border Layer of a Matrix ClockwiseArrange W, D, and L Results into Repeated WDL GroupsReorder a String by Alternating EndsBanking System with Top Activity AccountsSort Matrix Anti-Diagonals by Their Letter SequencesSubtract Product and Sum of Digits of a Large NumberCount Pair Sums with Point UpdatesSort Each Matrix Border and Fill ClockwiseData Challenge: Presentation + Coding (Python, Data Processing)Dynamic Wall Building and Range QueryQueue Check-in Simulation with Capacity LimitCheck Whether a Cyclic Shift Can Make the Array Strictly DescendingCount Numbers with Even Number of DigitsMinimum Increment Operations to Make Heights Strictly +/-1 MonotonicImplement a Given Array Algorithm (Iterative Reduction by First Non-zero)First Day Index Where Cumulative Visits Reach TargetSimple Bank System (Withdraw/Deposit/Transfer)Warehouse Package Allocation with Closures and ResetCount Case-Insensitive Symmetric Triplets in a StringPhone Battery Rotation With Recharge TimesReorder a Singly Linked List in L0→Ln→L1→Ln-1… OrderML Coding: Top-p (Nucleus) SamplingML Coding: Implement Linear Regression (from scratch)Implement Test HarnessMatrix ManipulationOrdered Fragment Pairs String-Counting ProblemRound-robin Server SimulationCount alternating odd/even subarraysMatrix operation maximum value - digit, +, -, right or down, can't change directionIf first and last letters are vowels, reverse the middle string

Capital One Featured Guides