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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
- Companies
- 11
- Topics
- 8
- Languages
Showing 121–150 of 427 results
- CitadelMediumSoftware EngineerCompute maximum later-earlier difference
This problem tests your ability to optimize an O(n^2) brute-force search into an O(n) linear-time solution using a single-pass scan while maintaining state variables.
Coding & AlgorithmsOnline AssessmentArraysOptimizationGreedy - CitadelHardSoftware EngineerEvery MEX Reachable With At Most One Bounded Increment
A coding problem about memory blocks with values below n: using at most one increment of a single value, never raising a value to n, list every minimum excluded value (MEX) the array can end up with. It tests careful case analysis of how one increment can open or fill a gap, handling duplicate values, and returning the sorted answer efficiently.
Coding & AlgorithmsOnline Assessment - CitadelHardSoftware EngineerEvery Reachable Priority Gap After At Most One Bounded Bump
Given n network ports each tagged with a priority code below n, find every value the lowest unused priority code could take after at most one bounded increment. Tests careful case analysis of how a single bump opens or closes a gap, and returning the answer efficiently.
Coding & AlgorithmsOnline Assessmentarrayscountingmex - CitadelHardSoftware EngineerFirst Free Locker Number After One Tag Bump
Given locker tags in [0, n-1], list every possible smallest missing tag after at most one capped +1 adjustment. Tests MEX reasoning, careful case analysis around duplicates, and an O(n) solution.
Coding & AlgorithmsOnline Assessmentarrayscountingcase-analysis - CitadelMediumSoftware EngineerMinimize changes for k-periodic palindrome
This question evaluates understanding of string algorithms and combinatorial reasoning, focusing on palindrome properties combined with k-periodicity and the ability to minimize character changes under global constraints.
Coding & AlgorithmsOnline Assessment - CitadelMediumSoftware EngineerMinimize image processing cost with discount
This question evaluates a candidate's competence in algorithm design and optimization, including interval-based cost aggregation and modular arithmetic for large-number results within the Coding & Algorithms domain.
Coding & AlgorithmsOnline Assessment - CodeiumMediumSoftware EngineerFind the third-largest word by length
This question evaluates proficiency in string and array manipulation, ordering by key metrics (string length), and handling tie-breaking via stable ordering, situated in the Coding & Algorithms domain.
Coding & AlgorithmsOnline Assessment - CoinbaseMediumSoftware EngineerDesign an in-memory database with TTL and backups
This question evaluates skills in designing and implementing in-memory data structures, TTL-based expiration, lexicographic prefix scans, and backup/restore snapshot semantics within the Coding & Algorithms domain.
Coding & AlgorithmsOnline Assessment - CoinbaseHardSoftware EngineerImplement a Coin-Constrained Jump Strategy
Design a pathfinding algorithm to reach a target coordinate in the minimum number of jumps subject to physics-based velocity adjustments, obstacle avoidance, and a non-negative coin balance constraint.
Coding & AlgorithmsOnline AssessmentBFSDynamic ProgrammingGraph Search - CoinbaseMediumSoftware EngineerImplement a versioned recipe management system
This question evaluates data-structure design and state-management competencies, covering CRUD, case-insensitive search/sort semantics, user management, and versioning/rollback for an in-memory Recipe Management System in the Coding & Algorithms domain.
Coding & AlgorithmsOnline Assessment - CoinbaseMediumSoftware EngineerImplement banking ops: transfer, top-k, cashback, merge
This question evaluates a candidate's ability to design a robust in-memory banking system, covering transactional correctness, idempotency, concurrency control, delayed cashback scheduling, aggregate top-k queries, and data structure and complexity trade-offs within the Coding & Algorithms domain.
Coding & AlgorithmsOnline Assessment - CoinbaseHardMachine Learning EngineerImplement local maxima, bagging, and k-means
This problem tests array traversal for local maxima detection, statistical resampling techniques for bagging, and iterative convergence for k-means clustering.
Coding & AlgorithmsOnline AssessmentAlgorithmsClusteringEnsemble Methods - CoinbaseMediumData ScientistSolve Aptitude Test: Logical, Numerical, Verbal Reasoning
This question evaluates logical, numerical, and verbal reasoning along with rapid pattern recognition and time-limited decision-making relevant to pre-employment aptitude screens for data science roles.
Coding & AlgorithmsOnline Assessment - Concentric AiMediumSoftware EngineerCount Students Outside Their Height-Sorted Positions
This problem tests your ability to compare a given array with its sorted version to identify indices where values do not match, assessing your proficiency in sorting and array indexing.
Coding & AlgorithmsOnline AssessmentArraysSortingImplementation - Concentric AiMediumSoftware EngineerMaximize Profit Under a Bitwise-OR Limit
Find a subset of items whose cumulative bitwise OR does not exceed a given limit such that the total profit is maximized.
Coding & AlgorithmsOnline Assessmentbit-manipulationgreedyarrays - Concentric AiMediumSoftware EngineerMinimize Population-Weighted Manhattan Travel Cost
This problem tests the ability to optimize a weighted distance metric by leveraging the independent nature of x and y coordinates in Manhattan geometry.
Coding & AlgorithmsOnline AssessmentArraysSortingMath - ConfluentMediumSoftware EngineerRank songs by pairwise user preferences
This question evaluates the ability to aggregate pairwise user preferences, implement majority-based comparison rules with deterministic tie-breakers, and compute a global ranking via beat counts.
Coding & AlgorithmsOnline Assessment - CrestaMediumSoftware EngineerCount the Leaves Left on a Grid After a Sequence of Wind Gusts
Simulate wind gusts over a grid in which every cell holds a number of leaves: each gust shifts all leaves one cell in its direction, and leaves pushed off the edge are lost for good. Return how many leaves remain, testing careful two-dimensional state updates and boundary handling under time pressure.
Coding & AlgorithmsOnline Assessment - CrestaMediumSoftware EngineerLongest Overlap Between the End of One String and the Start of Another
Given two strings, return the length of the longest suffix of the first string that is also a prefix of the second. The problem tests precise string indexing, the direction of the overlap, and boundary cases such as no overlap at all or an overlap covering the whole shorter string.
Coding & AlgorithmsOnline Assessment - DRWEasyData EngineerCompute a Year-End Balance with Monthly Card Fees
This problem tests logic implementation and data structure traversal, requiring the integration of conditional logic (fee waivers) into a sequential processing pipeline.
Coding & AlgorithmsOnline AssessmentData ProcessingLogicAggregation - DRWEasyData EngineerDelete the Fewest Characters to Avoid Triple Repeats
This problem tests string manipulation, greedy algorithm logic, and the ability to track character frequency counts to identify and prune violations of a constraint.
Coding & AlgorithmsOnline AssessmentStringsGreedyArrays - DRWEasyData EngineerImplement Nested Transactions in an In-Memory Database
This problem tests your ability to manage state and scope using stacks and dictionaries to implement transaction isolation in a key-value store.
Coding & AlgorithmsOnline AssessmentHash MapStackTransactions - DRWMediumSoftware EngineerSolve odd-string, digit swap, patient slot assignment
This multi-part problem evaluates string manipulation and parity/combinatorics for constructing odd-occurrence strings, greedy optimization and minimal-change reasoning for digit-swap distance minimization, and bipartite matching/assignment skills for patient slot allocation.
Coding & AlgorithmsOnline Assessment - DRWMediumSoftware EngineerSolve three algorithmic OA problems
This set evaluates algorithmic problem-solving skills including array manipulation and simulation for knockout tournament dynamics, graph traversal and constructive movement-sequence design on grids, and broader competencies in handling permutations, connectivity, and constraint-driven constructions.
Coding & AlgorithmsOnline Assessment - DRWMediumSoftware EngineerSolve three algorithmic OA tasks
Solve three algorithmic OA tasks 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 - DRWEasyData EngineerValidate a Password Against Explicit Security Rules
This problem tests string manipulation, character set validation, and the ability to apply a sequence of conditional checks efficiently.
Coding & AlgorithmsOnline AssessmentStringsValidationIteration - DisneyMediumData EngineerGenerate All Valid Combinations of Balanced Parentheses
This question tests a candidate's ability to apply recursive backtracking and combinatorial generation in a coding interview context. It evaluates understanding of constraint-based enumeration and string construction, core algorithmic skills frequently assessed in software engineering and data engineering roles.
Coding & AlgorithmsOnline Assessment - DisneyMediumData EngineerGenerate All Well-Formed Parenthesis Strings
This question tests practical understanding of recursion and backtracking through enumeration of all valid parenthesis combinations of a given length. It is a classic coding interview problem that evaluates combinatorial reasoning, constraint-based pruning, and familiarity with Catalan number sequences in algorithm design.
Coding & AlgorithmsOnline Assessment - DoorDashMediumSoftware EngineerSelect the best dasher for an order
This problem evaluates algorithmic selection and geometric computation skills—filtering eligible dashers, calculating Euclidean distances, and applying deterministic tie-breaking—within the Coding & Algorithms domain at an implementation-level algorithmic abstraction.
Coding & AlgorithmsOnline Assessment - ElevenlabsMediumSoftware EngineerCheapest Shirt Color Sequence With No Color Repeated on Consecutive Days
Buy one blue, green or red shirt on each of n days without buying the same color on consecutive days, and return the color sequence with the lowest total cost. The task asks for the actual sequence rather than only the cost, testing optimization over sequences and reconstruction of the unique optimal choice.
Coding & AlgorithmsOnline Assessment
Citadel
Coinbase
Confluent
Cresta
DRW
Disney
DoorDash
Elevenlabs