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Coding & Algorithms 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
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- 8
- Languages
Showing 91–120 of 427 results
- 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 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 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 OneMediumMachine Learning EngineerImplement string/matrix simulations and counting pairs
This problem tests string manipulation, simulation of grid-based gravitational collapse, and efficient combinatorial counting of string combinations.
Coding & AlgorithmsOnline AssessmentStringsSimulationHashing - 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 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 OneMediumMachine Learning EngineerRotate matrix and find max lamp coverage
This question evaluates array and matrix manipulation, in-place algorithm design, interval processing (sweep-line) and interval merging skills, testing competencies in algorithm design, complexity analysis, and robust edge-case reasoning within the Coding & Algorithms domain.
Coding & AlgorithmsOnline Assessment - 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 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 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 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 - Chicago Trading CompanyEasySoftware EngineerMerge Nested Dictionaries Iteratively
This question evaluates a candidate's skill in iterative data structure manipulation and handling of nested dictionary merging semantics, including conflict resolution and value overriding.
Coding & AlgorithmsOnline Assessment - CircleMediumSoftware EngineerImplement a simplified multi-level banking system
Implement a simplified multi-level banking system 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 & AlgorithmsOnline Assessment - CircleMediumSoftware EngineerImplement cheapest itinerary with date filters
This question evaluates proficiency in graph algorithms and constrained pathfinding, including handling date filters for initial departures, time-ordered connections, cycle avoidance, and quantitative complexity analysis.
Coding & AlgorithmsOnline Assessment - CiscoMediumSoftware EngineerSolve max-subarray, min-unique, and grid-jump
This question evaluates array algorithms and algorithmic problem-solving skills, specifically contiguous-sum optimization (greedy/DP reasoning), frequency counting and memory-constrained selection for unique minima, and grid traversal simulation with boundary and visit-state management.
Coding & AlgorithmsOnline Assessment - CitadelMediumSoftware EngineerCompute max team size with a core interval
This question evaluates algorithmic problem-solving around interval overlap and time-complexity optimization, measuring the ability to determine the maximum team size given a core interval while reasoning about interval intersections and scalability; it is commonly asked to assess correctness and subquadratic runtime thinking, categorized under Coding & Algorithms and emphasizing practical algorithmic implementation. The follow-up evaluates combinatorics and counting under adjacency constraints with modular arithmetic and efficient handling of large parameters, commonly posed to test recurrence reasoning and scalable counting approaches, falling under combinatorics/dynamic programming and emphasizing conceptual understanding linked to practical algorithmic efficiency.
Coding & AlgorithmsOnline Assessment
Capital One
Circle
Citadel