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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
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- 546
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- 11
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- 8
- Languages
Showing 1021–1050 of 3276 results
- DropboxMediumSoftware EngineerCompute worst-case guesses for adaptive hangman
This question evaluates algorithmic problem-solving, combinatorial reasoning, and adversarial information-theoretic thinking by requiring modeling of worst-case query strategies for adaptive letter-guessing.
Coding & AlgorithmsOnsite - DropboxMediumSoftware EngineerImplement KV Store and Token Bucket
This problem tests your ability to design a thread-safe in-memory key-value store and implement a rate limiter using the token bucket algorithm.
Coding & AlgorithmsOnsiteConcurrencyData StructuresRate Limiting - DropboxMediumSoftware EngineerImplement feedback for word guessing game
This question evaluates a candidate's ability to implement string-processing, frequency-counting, and membership-validation logic to generate exact and misplaced character matches for a word-guessing game.
Coding & AlgorithmsOnsite - DuolingoEasySoftware EngineerImplement String Encryption and Decryption
This problem tests your ability to manage character mapping and reverse lookups using dictionaries to perform basic string transformation and reconstruction.
Coding & AlgorithmsTechnical ScreenStringsDictionariesHash Maps - EightfoldaiMediumSoftware EngineerMake a Parentheses String Valid
This question evaluates proficiency in string manipulation and delimiter matching, specifically balancing parentheses while preserving character order and handling edge cases.
Coding & AlgorithmsTechnical Screen - ElasticMediumSoftware EngineerImplement log aggregation in React
This question evaluates a candidate's front-end development and real-time data-aggregation skills, specifically React component state management, handling streaming updates, choosing appropriate in-memory data structures (e.g., Map), and timestamp parsing/comparison for per-category frequency and last-update tracking.
Coding & AlgorithmsTechnical Screen - 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 - ElevenlabsMediumSoftware EngineerFewest Stones Left After Merging Equal-Level Pairs
Each stone has an integer level, and two stones of the same level can be merged into one stone of the next level, with merged stones able to merge again. Return the fewest stones that can remain after any sequence of merges, a problem that tests counting by level, cascading merges, and efficient handling of large inputs.
Coding & AlgorithmsOnline Assessment - ElevenlabsMediumSoftware EngineerSmallest Larger Integer That Uses None of the Digits of n
Given a positive integer below 2^31, find the smallest integer strictly greater than it that uses none of its decimal digits, or return -1 when no such integer exists. The problem tests reasoning about allowed digit sets, leading zeros, answers longer than the input, and results that exceed the 32-bit range.
Coding & AlgorithmsOnline Assessment - EnigmaMediumSoftware EngineerSearch Book Titles
This question evaluates proficiency in string processing, tokenization, case-insensitive matching, anagram detection, and algorithmic design for efficient search and deduplication.
Coding & AlgorithmsTechnical Screen - Epic SystemsMediumSoftware EngineerEncode Letters with a Telephone Keypad
Tests string manipulation, hash-table lookup, and state tracking by converting an alphanumeric string into multi-tap keypad strokes with pause delimiters.
Coding & AlgorithmsOnline AssessmentStringHash TableImplementation - EricssonMediumSoftware EngineerSolve Triangle Rows and Top Frequencies
This question set evaluates understanding of combinatorial number patterns and frequency-based selection, specifically the ability to generate an additive number triangle and to identify the k most frequent elements, assessing skills in array/list manipulation, counting, and selection algorithms.
Coding & AlgorithmsTechnical Screen - EthosMediumSoftware EngineerFind Array Elements Uniquely Determined by Known Range Sums
Given only the index ranges whose sums are known for a hidden integer array, list every position whose value is uniquely determined by those sums, or report -1 if none is. Tests reasoning about how overlapping and nested range sums combine, plus an efficient solution for 100,000 ranges.
Coding & AlgorithmsOnline Assessment - EtsyMediumData ScientistImplement streaming autocomplete under tight memory
This question evaluates a candidate's ability to design a memory- and latency-constrained autocomplete service, testing skills in data structure selection, string/Unicode normalization, approximate string matching, concurrency, dynamic updates, and algorithmic time/space analysis.
Coding & AlgorithmsTechnical Screen - ExoduspointMediumSoftware EngineerFind minimal time for four people crossing
This question evaluates algorithmic problem-solving and combinatorial optimization skills, focusing on reasoning about constrained pairing, state-space search, and minimizing total time under movement constraints.
Coding & AlgorithmsTechnical Screen - ExpediaMediumSoftware EngineerFind a Canonical Shortest Round Trip Through Flights
Find the shortest directed round trip starting and ending at a given airport, breaking ties lexicographically.
Coding & AlgorithmsOnsitegraphbfsshortest-path - ExpediaHardSoftware EngineerMaximum Sum Skyline
This problem tests your ability to optimize search spaces and use stack-based structures to maintain monotonic properties under specific geometric constraints.
Coding & AlgorithmsTechnical ScreenDynamic ProgrammingData StructuresOptimization - ExpediaHardSoftware EngineerSolve three interview coding problems
This multi-part question evaluates string manipulation, combinatorial counting, and constrained enumeration skills through sequence generation, palindromic-anagram substring counting, and wildcard digit-sum completion tasks.
Coding & AlgorithmsTechnical Screen - ExperianMediumData ScientistDesign Algorithm for Longest Increasing Subsequence Length
This question evaluates algorithm design and data structure skills, covering subsequence analysis, constraint/graph modeling for seating, and external-memory sorting considerations for scalability.
Coding & AlgorithmsTechnical Screen - F5NetworksMediumSoftware EngineerFind Top Hashtags
This question evaluates string parsing and tokenization, frequency counting of elements, time-window filtering of events, and the ability to sort results with deterministic tie-breaking rules.
Coding & AlgorithmsOnline Assessment - FaireMediumSoftware EngineerFind first 5-7-5 haiku in sentence
Find first 5-7-5 haiku in sentence 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 & AlgorithmsTechnical Screen - FaireMediumSoftware EngineerPeak number of bikes needed to cover all pre-booked rental intervals
Given every booking for a bike rental service as a start and end time, compute the peak number of bikes in use at the same moment, which is the smallest fleet that serves all bookings. Tests interval-overlap reasoning, half-open boundary handling and an efficient method for up to 100,000 unsorted bookings.
Coding & AlgorithmsOnsite - FaireMediumSoftware EngineerPrint a Centered Pascal Triangle
This question evaluates the ability to generate combinatorial structures (Pascal's triangle) and apply precise numeric formatting, alignment, and string-layout skills, reflecting algorithmic thinking and attention to presentation details.
Coding & AlgorithmsTechnical Screen - FanaticsMediumSoftware EngineerPlot ASCII chart for time-price pairs
This question evaluates skills in array manipulation, coordinate mapping, and ASCII-based data visualization, focusing on transforming unsorted time-price pairs into a fixed 2D grid and handling point collisions and empty cells.
Coding & AlgorithmsTechnical Screen - FidelityMediumSoftware EngineerCompare Spring and Spring Boot
Compare Spring and Spring Boot 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 - FidelityMediumSoftware EngineerDescribe Java 8 features
Describe Java 8 features 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 - FidelityMediumSoftware EngineerSolve concurrency in Java
Solve concurrency in Java 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 - FigmaMediumSoftware EngineerCheck Graph Reachability For File Permissions
Practice graph reachability for simplified file-permission inheritance under directed, undirected, and blocked-edge variants. The prompt is useful for reviewing DFS or BFS, visited sets, cycle handling, and clarifying traversal semantics.
Coding & AlgorithmsTechnical Screen - FigmaMediumSoftware EngineerConvert Leveled Rich-Text Tokens into Nested Lists
Tests parsing a linear sequence of leveled tokens into a hierarchical tree or nested list structure using stack-based tree construction.
Coding & AlgorithmsOnsiteStackTreeAlgorithms - FigmaMediumSoftware EngineerDesign document layer with undo/redo
This question evaluates a candidate's understanding of reversible state mutation and undo/redo semantics, covering batching, inverse operation representation, operation compression, failure handling, and choice of data structures for edit history.
Coding & AlgorithmsTechnical Screen
Dropbox
Elevenlabs
Expedia
Experian
Faire
Fidelity
Figma