Coding & Algorithms interview questions

Showing 2461–2490 of 3276 results

• Aggregate user logs into 30-minute sessionsHard

  This question evaluates data engineering competencies in time-series sessionization, datetime parsing and arithmetic, grouping and aggregation, distinct-count computation, and CSV log processing.

  RobinhoodData EngineerCoding & AlgorithmsTechnical Screen
• Build a Weekly CalendarMedium

  This question evaluates frontend UI engineering skills, focusing on interactive interface construction, event handling, and state modeling to maintain a single source of truth for events in a weekly calendar grid, and it belongs to the web frontend development and UI/state-management domain.

  RobinhoodFrontend EngineerCoding & AlgorithmsOnsite
• Compute Load Factors in a Service Dependency DAGMedium

  Calculate downstream request multipliers for services in a directed acyclic graph (DAG) starting from an entrypoint service, accounting for converging dependency paths and unreachable nodes.

  RobinhoodSoftware EngineerCoding & AlgorithmsTechnical Screen
• Compute dependency load factors in a DAGMedium

  This problem tests your ability to model dependencies in a Directed Acyclic Graph (DAG) and calculate the cumulative 'load' contribution of each node, requiring efficient graph traversal techniques like topological sorting or recursion with memoization.

  RobinhoodSoftware EngineerCoding & AlgorithmsTechnical Screen
• Compute nearest gate distance in gridMedium

  This problem tests your ability to perform multi-source Breadth-First Search (BFS) on a grid to find the shortest distance from every cell to the nearest target (gate).

  RobinhoodSoftware EngineerCoding & AlgorithmsTechnical Screen
• Compute trigger counts in a DAGEasy

  This question evaluates understanding of directed acyclic graphs, graph traversal and accumulation of values across dependency edges, as well as algorithmic efficiency for handling large sparse graphs.

  RobinhoodSoftware EngineerCoding & AlgorithmsTechnical Screen
• Count Unique Dependents in a Referral DAGHard

  Count unique direct and transitive dependents in a DAG, preserving edge direction, ignoring unknown endpoints, and handling shared descendants without double-counting.

  RobinhoodSoftware EngineerCoding & AlgorithmsOnsite
• Count and Rank Words in a ParagraphMedium

  This problem tests string manipulation, hash map usage for frequency counting, and custom sorting logic for deterministic ordering.

  RobinhoodBackend EngineerCoding & AlgorithmsTechnical Screen
• Design a constrained cache and secure string validatorMedium

  This question tests the ability to implement a thread-safe, size-constrained cache (LRU-like) and robust string validation logic for identifying malformed or potentially malicious input strings.

  RobinhoodSoftware EngineerCoding & AlgorithmsOnsite
• Design a referral leaderboard with chain-based countsMedium

  This question evaluates a candidate's ability to model and compute transitive referral counts using graph-like structures and efficient data structures, testing skills in algorithm design, counting, and sorting within the Coding & Algorithms domain.

  RobinhoodSoftware EngineerCoding & AlgorithmsOnsite
• Design in-memory payment and friendship systemEasy

  This question evaluates object-oriented design skills, stateful in-memory data structures, request processing, and correctness constraints such as friend relationships, unique request IDs, and atomic balance transfers.

  RobinhoodSoftware EngineerCoding & AlgorithmsTechnical Screen
• Flatten Fractional-Share Inventory and Record Trade LogsMedium

  Process fractional-share buys and sells with exact hundredth units, whole-share market flattening, dollar-order conversion, and ordered inventory-perspective logs.

  RobinhoodSoftware EngineerCoding & AlgorithmsTechnical Screen
• Identify Overlapping Sessions and Optimize CoverageMedium

  This interview question evaluates algorithm design, data structures, correctness, complexity, edge cases, and implementation details in a realistic interview setting. A strong answer for Identify Overlapping Sessions and Optimize Coverage states assumptions, handles edge cases, explains trade-offs, and shows how to validate the result clearly.

  RobinhoodData ScientistCoding & AlgorithmsTechnical Screen
• Implement string-based candlestick classifierMedium

  This question evaluates string parsing, streaming input processing, numeric validation, and attention to time/space complexity in the Coding & Algorithms category, focusing on efficient single-pass parsing and O(1) extra space constraints.

  RobinhoodSoftware EngineerCoding & AlgorithmsTechnical Screen
• Maintain Fractional Stock Inventory Across OrdersMedium

  Simulate sequential customer fractional buy and sell orders, using scaled integer arithmetic to maintain the firm's remaining inventory between 0 and 1 share while tracking whole-share market executions.

  RobinhoodSoftware EngineerCoding & AlgorithmsOnsite
• Parse Requests and Compute BalancesMedium

  This problem tests your ability to parse structured text commands, manage relational state between users, and implement transactional logic with integrity constraints.

  RobinhoodSoftware EngineerCoding & AlgorithmsOnsite
• Produce a Deterministic Course PlanMedium

  Return the lexicographically smallest valid course order from prerequisite pairs, or report a cycle. Handle duplicate edges, malformed IDs, self-dependencies, empty course sets, and large graphs with deterministic topological sorting.

  RobinhoodSoftware EngineerCoding & AlgorithmsOnsite
• Count Distinct Hat Assignments and Maximize Hat PointsHard

  Count valid one-hat-per-person assignments and maximize assigned-hat points with exact counts, unique hat use, and bitmask or backtracking reasoning.

  RobloxSoftware EngineerCoding & AlgorithmsOnsite
• Data Center Rack Units: Can a Centered Equipment Bay Be Reserved?Medium

  Process an online stream of rack-unit reservations and span-availability checks over an infinite 1D coordinate line, answering each availability check with the data seen so far.

  RobloxSoftware EngineerCoding & AlgorithmsOnline Assessment
• Design robot path boundedness with repeatsMedium

  This question evaluates algorithmic skills in parsing compressed instruction strings, finite-state simulation, and spatial reasoning to determine path boundedness, and it belongs to the Coding & Algorithms domain.

  RobloxSoftware EngineerCoding & AlgorithmsOnsite
• Detect robot state after movementsMedium

  This interview question evaluates algorithm design, data structures, correctness, complexity, edge cases, and implementation details in a realistic interview setting. A strong answer for Detect robot state after movements states assumptions, handles edge cases, explains trade-offs, and shows how to validate the result clearly.

  RobloxSoftware EngineerCoding & AlgorithmsOnsite
• Detect runs and collapse a numeric gridMedium

  This question evaluates proficiency in 2D array manipulation, pattern detection for contiguous runs, and state simulation involving removal and gravity-like collapse of elements.

  RobloxSoftware EngineerCoding & AlgorithmsOnsite
• Extend counter to per-client rate limitingEasy

  This question evaluates competency in designing per-client, time-windowed rate limiting using efficient data structures for time-based eviction and counting within the Coding & Algorithms domain.

  RobloxMachine Learning EngineerCoding & AlgorithmsTechnical Screen
• Find Windows Containing a TargetMedium

  This problem tests your ability to efficiently filter and identify intervals within a collection that satisfy specific containment constraints using two-pointer or sliding window techniques.

  RobloxMachine Learning EngineerCoding & AlgorithmsOnsite
• Find largest digit-sum bucket sizeMedium

  This question evaluates a candidate's competency in combinatorial counting, digit-sum properties, and algorithmic optimization for range queries within the Coding & Algorithms domain.

  RobloxSoftware EngineerCoding & AlgorithmsTechnical Screen
• Find maximum follow depth using recursionEasy

  This question evaluates a candidate's competency with recursion, directed graph traversal, cycle detection, and memoization when computing longest-path depths in social-network-style follow graphs.

  RobloxData ScientistCoding & AlgorithmsTechnical Screen
• Find most frequent call path in logsMedium

  This problem tests your ability to parse structured log strings representing nested function calls into a hierarchical tree and identify the most frequently occurring execution path.

  RobloxSoftware EngineerCoding & AlgorithmsTechnical Screen
• Find target-heavy sliding windowsMedium

  This question tests the ability to implement an efficient sliding window algorithm to analyze frequency-based patterns within a data stream or array.

  RobloxMachine Learning EngineerCoding & AlgorithmsOnsite
• Find the Longest Safe Straight-Line Movement on a Laser GridMedium

  Find a robot's longest safe straight-line movement on a laser-covered grid, where only the initial cell is protected and laser rows and columns are blocked.

  RobloxSoftware EngineerCoding & AlgorithmsOnline Assessment
• Find the Most Frequent Log CallEasy

  This question evaluates a candidate's ability to perform frequency analysis on sequences, demonstrating competency with data structures for counting occurrences and with algorithmic time and space complexity considerations.

  RobloxMachine Learning EngineerCoding & AlgorithmsTechnical Screen