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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.
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Showing 2401–2430 of 3276 results
- RampMediumSoftware EngineerPer-IP Sliding-Window Rate Limiter: Accept or Reject Each Request
Implement a per-IP sliding-window rate limiter: given request timestamps, IP addresses, a request limit and a window length, decide in order whether each request is accepted or rejected. Tests exact window-boundary semantics, per-IP state, and processing a request log efficiently.
Coding & AlgorithmsOnline Assessment - RampMediumSoftware EngineerSpreadsheet String Concatenation with Dependent Cells
Build a fixed-grid string spreadsheet with concatenation formulas, dependency updates, repeated references, and read-time circular-reference errors.
Coding & AlgorithmsOnsite - RampHardSoftware EngineerTrack Users From Flight History
This question evaluates competency in processing and aggregating temporal event data, including time-interval reasoning, counting/grouping per user, and designing efficient data structures and algorithms for large datasets.
Coding & AlgorithmsTechnical Screen - RampHardSoftware EngineerTraverse an HTTP Maze with Retry Handling
This problem tests BFS traversal skills combined with state management for handling intermittent network failures and API constraints.
Coding & AlgorithmsOnsiteBFSGraphAPI - RbcroyalbankMediumMachine Learning EngineerProcess Operations for an In-Memory Key-Value Store
This problem tests proficiency with hash map operations and handling data retrieval edge cases within an in-memory data store.
Coding & AlgorithmsTechnical ScreenHash MapData StructuresAlgorithms - Read.AiMediumSoftware EngineerCompare Sentences Using Transitive Synonym Groups
Compare two tokenized sentences using undirected, transitive synonym relationships. Sentence lengths and word positions must match, while a union-find or graph traversal groups chained synonyms and leaves unknown words equivalent only to themselves.
Coding & AlgorithmsTechnical Screen - RedditMediumMachine Learning EngineerExclude Cat- or Dog-Related Comments and All Their Replies by Reader Mode
Given discussion comments that form reply trees, each flagged as being about cats, dogs, both or neither, return every comment a cat person or a dog person should not see, where hiding a comment also hides all of its replies. Tests reasoning over tree structure, edge cases such as missing parents, and complexity analysis.
Coding & AlgorithmsOnsite - RedditMediumSoftware EngineerFind a Word Along One Fixed Direction in a Grid
Search a letter grid for a word along one fixed direction, with explicit diagonal rules, boundaries, and rejection of paths that turn.
Coding & AlgorithmsTechnical Screen - RedditMediumSoftware EngineerFind word sequence with 1–2 char changes
This question evaluates graph traversal and shortest-path search skills, specifically reasoning about BFS vs DFS, string transformation modeling, and algorithmic time/space complexity within the Coding & Algorithms domain.
Coding & AlgorithmsTechnical Screen - RedditMediumMachine Learning EngineerImplement a simplified memcached server
This problem tests your ability to design a thread-safe, in-memory key-value store and implement basic command parsing for an asynchronous network service.
Coding & AlgorithmsTechnical ScreenConcurrencyData StructuresCaching - RedditMediumSoftware EngineerImplement a sliding-window rate limiter
This problem tests your ability to design a rate-limiting algorithm that calculates traffic volume within a sliding time window to prevent API abuse.
Coding & AlgorithmsOnsiteHash MapSliding WindowRate Limiting - RedditMediumSoftware EngineerMerge Message Context Windows
This problem tests your ability to merge overlapping intervals efficiently using sorting and greedy techniques, a foundational skill for data reconciliation tasks.
Coding & AlgorithmsOnsiteIntervalsSortingGreedy - RedditMediumSoftware EngineerModerator System with Ranking, Communities, and Demotion
Design and implement an in-memory moderator management system supporting community-specific hierarchies, seniority-based permissions, and rank mutations.
Coding & AlgorithmsTechnical ScreenDesignHash TableLinked List - RedditHardMachine Learning EngineerSolve palindrome and list tasks
This problem tests your ability to manipulate string prefixes to satisfy palindromic properties and your skill in performing in-place linked list reordering based on node index parity.
Coding & AlgorithmsOnsiteStringLinked ListTwo Pointers - ReevoMediumSoftware EngineerCheck strings against dictionary efficiently
This question evaluates skills in efficient membership testing for large datasets, memory-time trade-offs in data structures, and string handling concerns such as case sensitivity and Unicode normalization.
Coding & AlgorithmsOnline Assessment - ReevoMediumSoftware EngineerCount all palindromic substrings
This question evaluates proficiency with string algorithms and algorithmic problem-solving, focusing on palindrome detection and counting contiguous substrings. It is commonly asked to assess implementation skills and the ability to reason about time and space complexity within the Coding & Algorithms domain, emphasizing practical application rather than purely conceptual understanding.
Coding & AlgorithmsOnline Assessment - Reinforce LabsMediumSoftware EngineerCompute minimum added stones to balance a tree
This problem tests tree traversal techniques and greedy aggregation, requiring you to determine the minimum number of 'stones' needed to equalize all subtree sums to match a target value.
Coding & AlgorithmsOnline AssessmentTreesGreedyRecursion - RemitlyEasySoftware EngineerCompute transfers to balance account debts
This question evaluates a candidate's ability to convert per-account net balances into a set of transfers, testing algorithmic problem solving, data-structure manipulation, and correctness under conservation invariants in transactional systems.
Coding & AlgorithmsTechnical Screen - RemitlyMediumSoftware EngineerDesign an Elevator System and Scheduler
This question evaluates a candidate's object-oriented design and algorithmic scheduling competencies, focusing on concurrency control, fault tolerance, queue management, tie-breaking rules, and time/space complexity analysis within an elevator control system.
Coding & AlgorithmsOnsite - RemitlyMediumSoftware EngineerSolve k-Nearest Places by Latitude/Longitude
This question evaluates geospatial algorithm and systems-design competencies, focusing on nearest-neighbor search, great-circle distance computation, spatial indexing, and runtime/memory trade-offs for scalable location queries.
Coding & AlgorithmsOnsite - RemitlyMediumSoftware EngineerValidate a Bijective Substitution Cipher
Determine whether two printable ASCII strings form a valid one-to-one and onto (bijective) character substitution mapping.
Coding & AlgorithmsOnsiteHash TableStringAlgorithms - RenderMediumSoftware EngineerCount Blocked Rate-Limited Requests
This question evaluates understanding of rate-limiting logic, sliding-window time-based counting, and data structure design for tracking per-IP and per-(IP, host) request histories.
Coding & AlgorithmsTechnical Screen - RenderMediumSoftware EngineerFind the Five Busiest Client IPs in Request Logs
Aggregate completed HTTP request logs across files to find the top five client IPv4 addresses, excluding auxiliary messages and applying deterministic count ties.
Coding & AlgorithmsTechnical Screen - Retell AIEasySoftware EngineerEvaluate a Small Stack-Based Integer Language
Implement an interpreter for a stack-based integer language supporting arithmetic, stack manipulation, output, and immediate error reporting with partial output preservation.
Coding & AlgorithmsTechnical Screenstackparsingsimulation - Retell AIMediumSoftware EngineerQuery an Indexed In-Memory Numeric Table
This problem tests the ability to implement efficient multi-column indexing using binary search and sorted set intersections to handle complex range queries.
Coding & AlgorithmsTechnical ScreenData StructuresBinary SearchIndexing - RetoolMediumSoftware EngineerCompute max profit with forced trades
Compute max profit with forced trades 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 - RevolutMediumSoftware EngineerImplement a random fixed-size load balancer
This question evaluates understanding of randomized selection, efficient in-memory data structures, and API/state management for a fixed-capacity load balancer that must support addNode, removeNode, and uniform random routing while handling duplicates, removals, and empty-state behavior.
Coding & AlgorithmsTechnical Screen - RevolutMediumSoftware EngineerImplement a thread-safe money transfer
This question evaluates a candidate's mastery of concurrent programming and data-integrity principles, focusing on thread safety, atomic state updates, and deadlock avoidance when transferring funds between shared accounts.
Coding & AlgorithmsTechnical Screen - RilletMediumBackend EngineerDistribute Annual Revenue Across Twelve Months
This problem tests logic, integer arithmetic, and edge-case handling by requiring the distribution of a total sum into equal parts while managing remainders without using floating-point numbers.
Coding & AlgorithmsTechnical ScreenAlgorithmsInteger ArithmeticData Manipulation - RiotgamesEasySoftware EngineerAggregate Letter-Number Groups
This problem tests string parsing, data aggregation using a hash map, and sorting techniques.
Coding & AlgorithmsTechnical ScreenStringsHash MapsSorting
Ramp
Reddit
Remitly
Retell AI
Revolut