Coding & Algorithms interview questions

Showing 2011–2040 of 3276 results

• Build Ranked Feed With Photo BatchingMedium

  This question evaluates algorithmic reasoning and data manipulation skills, including stable sorting, grouping/batching, and merging of ranked items while preserving ordering invariants.

  NextdoorMachine Learning EngineerCoding & AlgorithmsTechnical Screen
• Flatten Nested CommentsEasy

  This problem tests your ability to traverse a nested tree structure (comments) and flatten it into a linear representation while respecting hierarchical depth levels.

  NextdooriOS EngineerCoding & AlgorithmsTechnical Screen
• Group Photos and Sort Feed ItemsMedium

  Implement a feed transformation that collapses consecutive photo posts by the same user into album items and then stably sorts the resulting feed by timestamp.

  NextdoorSoftware EngineerCoding & AlgorithmsTechnical Screen
• Implement ordering with dependency constraintsMedium

  This question evaluates understanding of dependency resolution and ordering within graph-based problems, including cycle detection, lexicographic tie-breaking, and extensions requiring certain items to appear as contiguous groups.

  NextdoorMachine Learning EngineerCoding & AlgorithmsTechnical Screen
• Implement version string comparator with extensionsMedium

  This question evaluates string parsing and comparison algorithms, handling of numeric versus lexical ordering and versioning semantics (including pre-release identifiers and ignored build metadata), within the Coding & Algorithms domain.

  NextdoorSoftware EngineerCoding & AlgorithmsTechnical Screen
• Merge overlapping weekly time intervalsMedium

  This question evaluates the ability to parse weekday and 24-hour time strings, reason about interval overlap, and apply efficient merging and sorting techniques for time-based intervals.

  NextdoorMachine Learning EngineerCoding & AlgorithmsTechnical Screen
• Simulate Transaction Lock SchedulingHard

  Implement an in-memory lock manager simulating shared and exclusive lock scheduling with strict FIFO queuing to prevent starvation.

  NextdoorSoftware EngineerCoding & AlgorithmsTechnical Screen
• Write SQL for app metricsHard

  This question evaluates proficiency in SQL-based data engineering, focusing on time-zone-aware timestamp handling, aggregation of event and relationship data, cohort retention analysis, and computation of product metrics like DAU, new users, photo activity, and follower distributions.

  NextdoorData EngineerCoding & AlgorithmsTechnical Screen
• Write SQL for basic user metricsHard

  This question evaluates proficiency in SQL for relational databases, specifically testing aggregation, joins, date/time grouping, and handling tied results when computing user metrics such as total users, peak signup month, and top-followed users.

  NextdoorData EngineerCoding & AlgorithmsTechnical Screen
• Generate Color Feedback for a Word GuessMedium

  Generate green, yellow, or red feedback for each character in a word guess based on positional equality and presence anywhere in the answer. Follow the stated presence semantics, where misplaced duplicate letters remain yellow rather than consuming a limited match count.

  NgrokSoftware EngineerCoding & AlgorithmsTechnical Screen
• Prefix Tree Supporting Insert, Exact Search and Prefix QueriesMedium

  A coding problem that processes a sequence of insert, exact-match search and prefix-check operations on lowercase words and returns the boolean answers to the queries in order. It tests building a character-level word index and correctly separating whole-word matches from words that are only prefixes of others.

  NielsenSoftware EngineerCoding & AlgorithmsOther
• Find kth smallest and count stair-climbing waysMedium

  This problem tests your ability to implement an efficient selection algorithm for order statistics and a dynamic programming approach to solve a classic combinatorial staircase problem.

  NioSoftware EngineerCoding & AlgorithmsTechnical Screen
• Implement a BFS web crawlerMedium

  This question evaluates proficiency in breadth-first search and graph traversal concepts applied to web crawling, including handling duplicate links, hostname filtering, and tracking visited URLs.

  NooksSoftware EngineerCoding & AlgorithmsOnsite
• Design a text editor with undo/redoMedium

  This question evaluates understanding of stateful data structures, operation/command semantics for reversible actions, undo/redo stack management, interface design, complexity analysis, and test coverage for mutable editors.

  NotionSoftware EngineerCoding & AlgorithmsTechnical Screen
• Find Top Errors in Time WindowMedium

  This problem tests your ability to process streaming log data within a sliding time window, aggregate frequencies using hash maps, and implement custom sorting logic.

  NotionSoftware EngineerCoding & AlgorithmsOnsite
• Assign Robots to Nearest Pickup Items on a Grid with ObstaclesMedium

  Given a grid with blocked cells, k delivery robots and k pickup items, assign every robot exactly one item by repeatedly matching the closest remaining robot-item pair under fixed tie-breaking rules. It tests shortest-path distances on grids with obstacles and careful, deterministic greedy assignment.

  NuroSoftware EngineerCoding & AlgorithmsTechnical Screen
• Check Vertical Reflection Symmetry with Duplicate PointsHard

  Determine whether a multiset of 2D points is symmetric across a vertical line, preserving duplicate counts and allowing half-integer axes.

  NuroSoftware EngineerCoding & AlgorithmsTechnical Screen
• Find Intersections Between Two Interval ListsMedium

  This problem tests your ability to efficiently merge and find overlaps between two sorted interval lists using a two-pointer approach.

  NuroSoftware EngineerCoding & AlgorithmsTechnical Screen
• Find Maximum Path Sum in N-ary TreeHard

  This question evaluates understanding of tree traversal and aggregation techniques, including handling of variable-arity nodes, negative values, and path-based dynamic programming on N-ary trees.

  NuroMachine Learning EngineerCoding & AlgorithmsTechnical Screen
• Find gaps between intervalsMedium

  This question evaluates interval manipulation and range-coverage reasoning, testing skills in sorting, merging overlapping ranges, and handling boundary conditions within the Coding & Algorithms domain.

  NuroSoftware EngineerCoding & AlgorithmsTechnical Screen
• Generate Weighted Random Keys With Add And RemoveMedium

  This problem tests your ability to efficiently manage a collection of weighted items and perform random sampling based on those weights, requiring O(log N) updates and lookups.

  NuroSoftware EngineerCoding & AlgorithmsTechnical Screen
• Group points by distance thresholdMedium

  This problem tests your ability to efficiently group spatial points based on proximity using graph traversal or clustering techniques while managing computational complexity.

  NuroSoftware EngineerCoding & AlgorithmsTechnical Screen
• Implement BFS and a Job SchedulerHard

  Solve grid reveal with BFS and design a thread-safe periodic job scheduler. The solution covers Minesweeper-style expansion, queue processing, priority-queue scheduling, locks, worker pools, cancellation, duplicate prevention, long-running tasks, clock drift, and backpressure.

  NuroBackend EngineerCoding & AlgorithmsOnsite
• Map Weighted Random Draws to IndicesMedium

  This problem tests your ability to efficiently map a series of random draws to specific indices based on provided weights using binary search techniques.

  NuroSoftware EngineerCoding & AlgorithmsTechnical Screen
• Maximize Revenue With Two Contiguous Delivery RoutesMedium

  This problem tests dynamic programming and prefix-max techniques to find the maximum revenue of two non-overlapping subarrays with given length constraints.

  NuroSoftware EngineerCoding & AlgorithmsTechnical Screen
• Pick Two Trees for a Zipline That Maximizes Height Times SpanMedium

  A coding question that recasts the classic two-line container problem as choosing two trees in a row to string a zipline between. It asks for the largest value of the shorter tree's height times the distance between the two trees, over arrays of up to 100,000 heights, and tests efficient pair selection.

  NuroSoftware EngineerCoding & AlgorithmsTechnical Screen
• Reveal a Minesweeper BoardMedium

  This problem tests recursive graph traversal (DFS/BFS) and grid manipulation logic to implement the recursive uncovering mechanism found in Minesweeper.

  NuroSoftware EngineerCoding & AlgorithmsTechnical Screen
• Reveal a Minesweeper Region with Adjacent-Mine CountsHard

  Implement a Minesweeper cell-reveal algorithm that dynamically calculates 8-directional mine adjacencies and expands blank regions while safely avoiding recursion depth pitfalls on large boards.

  NuroSoftware EngineerCoding & AlgorithmsTechnical Screen
• Find Peak Memory Usage Across Process IntervalsHard

  Calculate the peak simultaneous memory usage from a set of half-open intervals and identify the earliest continuous time window sustaining that peak.

  NutanixSoftware EngineerCoding & AlgorithmsTechnical Screen
• Find the Most Reliable Path Through a NetworkHard

  Implement an algorithm to find the maximum end-to-end success probability between two nodes in an undirected network with multiplicative edge probabilities. Tests graph traversal, Dijkstra's algorithm variant with max-heaps, and edge-case handling.

  NutanixSoftware EngineerCoding & AlgorithmsTechnical Screen