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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 451–480 of 1080 results
- GoogleEasySoftware EngineerSolve three coding problems
This set of problems evaluates algorithmic problem-solving across combinatorics and enumeration (finding the N-th lexicographic license plate), constrained geometric and graph traversal reasoning (counting Android-style 3x3 unlock patterns), and interval-processing algorithms (computing intersections of sorted, non-overlapping intervals) within the domain of algorithms and data structures. These questions are commonly asked because they reveal ability to reason about discrete enumeration, constraint handling, and efficient time/space implementations for edge-case-heavy inputs, and the level of abstraction spans both conceptual understanding (combinatorial and geometric constraints) and practical application (efficient algorithm and data-structure implementation).
Coding & AlgorithmsOnsite - GoogleMediumSoftware EngineerStreaming Points: Remove Any Pair Within a Distance
This problem tests the ability to maintain and query a dynamic sorted collection of points to perform efficient proximity-based removals.
Coding & AlgorithmsOnsiteSorted StructuresGreedyBST - GoogleMediumSoftware EngineerTrack Island Counts as Land Is Added
Report the initial number of grid islands and update that count after each requested water-to-land addition. The problem probes incremental connectivity, duplicate additions, local merge effects, scalability to large grids, and alternatives to recomputing the entire map.
Coding & AlgorithmsOnsite - GoogleMediumSoftware EngineerTroubleshoot CPU, latency, and DNS issues
This question evaluates system troubleshooting and diagnostic competencies, including Linux CPU and IO performance analysis, network latency and packet-level investigation, and DNS resolution and query tooling knowledge.
Coding & AlgorithmsOnsite - GrammarlyMediumSoftware EngineerImplement a Transactional Key-Value Store
This question evaluates understanding of transactional state management, data structure design, and consistency/visibility semantics in an in-memory key-value store that supports nested transactions.
Coding & AlgorithmsOnsite - GrammarlyMediumSoftware EngineerMerge overlapping corrections
This question evaluates a candidate's ability to manage and manipulate overlapping intervals with multi-criteria tie-breaking, preserve original metadata across splits, and design efficient data structures and algorithms for producing non-overlapping correction spans.
Coding & AlgorithmsOnsite - HarveyHardSoftware EngineerBuild an In-Memory File Vault with Duplicate-Name Handling
Design an in-memory hierarchical file vault supporting automatic directory creation, lexicographical directory listings, and duplicate-name resolution using the smallest available numeric suffix.
Coding & AlgorithmsOnsiteTrieDesignTree - HarveyMediumSoftware EngineerDesign Spreadsheet Formula Cells
This question evaluates ability to design and implement data structures and algorithms for expression parsing, dependency tracking, incremental evaluation, and cycle detection in an in-memory spreadsheet.
Coding & AlgorithmsOnsite - HarveyMediumSoftware EngineerEvaluate Symbol Expressions
Implement an expression evaluator for a dictionary of symbolic definitions with arithmetic operations, resolving dependencies, and detecting cycles and undefined references.
Coding & AlgorithmsOnsitedirected-graphtopological-sortexpression-parsing - HarveyMediumSoftware EngineerImplement a Cursor-Based Text Editor
Design an in-memory cursor-based text editor supporting character insertion, deletion, and cursor navigation with efficient time complexity.
Coding & AlgorithmsOnsitedata-structuresstackdesign - HarveyMediumSoftware EngineerImplement a Database Connection Pool
Tests your ability to implement a thread-safe connection pool that manages connection lifecycles, blocking acquisition with timeouts, and resource reuse under concurrent access.
Coding & AlgorithmsOnsiteConcurrencyMultithreadingObject-Oriented Design - HarveyMediumBackend EngineerImplement tag matcher and filesystem
This combined prompt evaluates string-processing and parsing skills for tag matching and design/implementation skills for an in-memory file system, measuring competencies in exact whole-word matching, case normalization, punctuation and duplicate handling, path parsing, hierarchical data structures, and file API behaviors.
Coding & AlgorithmsOnsite - HarveyMediumSoftware EngineerIn-Memory File System: Create, Track Duplicates, and List
Design an in-memory file system supporting directory creation, file creation with automated duplicate-name collision resolution, content retrieval, and directory listing.
Coding & AlgorithmsOnsiteTrieDesignTree - HebbiaHardSoftware EngineerDetect a Winner on a 3x3 Tic-Tac-Toe Board
This problem tests your ability to efficiently represent board states and implement win-condition logic for a grid-based game.
Coding & AlgorithmsOnsiteArraysLogicGames - HebbiaMediumSoftware EngineerImplement a Cache Snapshot Printer
This question evaluates understanding of LRU cache semantics, data structures for maintaining recency and eviction, and techniques for serializing or compressing state by grouping identical values while preserving ordering.
Coding & AlgorithmsOnsite - HubSpotEasySoftware EngineerFind a special person using knows(a,b)
This question evaluates algorithmic reasoning about pairwise relation inference using an oracle-style knows(a, b) API and the ability to minimize API calls, testing skills in graph modeling and asymptotic analysis.
Coding & AlgorithmsOnsite - HubSpotMediumSoftware EngineerFind spammer with minimal hasMessaged calls
Find the "spammer" account that messaged every other account but received from none, using only a hasMessaged(a, b) oracle. This is the classic find-the-celebrity problem inverted, solved with a two-phase elimination-then-verify algorithm in O(n) oracle calls and O(1) extra space, with full correctness proof and edge-case handling.
Coding & AlgorithmsOnsite - Hudson River TradingEasyMachine Learning EngineerCount People Reaching the Boundary
This question evaluates algorithmic simulation and event-driven modeling skills, specifically handling discrete versus continuous time, visibility constraints relative to a stationary watcher that changes facing direction, and boundary conditions for state transitions.
Coding & AlgorithmsOnsite - Hudson River TradingHardSoftware EngineerImplement Order Modification Feature
This question evaluates a software engineering competency in modifying and extending a C++ client/server trading system, focusing on state management, input validation, API integration, and maintaining invariants for order lifecycle.
Coding & AlgorithmsOnsite - IllumioMediumSoftware EngineerCount Regions in a Binary Grid
This problem tests your ability to navigate a 2D grid and identify connected components using graph traversal techniques like Depth-First Search (DFS) or Breadth-First Search (BFS).
Coding & AlgorithmsOnsiteDFSBFSGraph - IllumioMediumSoftware EngineerSolve Matrix Traversal and Pair Sum
This problem tests your ability to manipulate 2D matrix indices for spiral traversal and apply efficient hash-based lookups to solve the two-sum problem within a specific sequence.
Coding & AlgorithmsOnsiteMatrixArrayHash Table - InstacartMediumSoftware EngineerCalculate a Basket Total from Delimited Product Records
Parse pipe-delimited shopping cart records to compute the total basket cost in integer cents, properly accumulating repeated SKUs and handling zero-quantity items.
Coding & AlgorithmsOnsitestringsparsinghash-table - InstacartMediumSoftware EngineerCompute and optimize average wait time
This question evaluates skills in scheduling and queueing algorithms, simulation of service systems, and reasoning about time and space complexity when computing average waiting times.
Coding & AlgorithmsOnsite - InstacartMediumSoftware EngineerCompute average customer waiting time
Compute average customer waiting time 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 & AlgorithmsOnsite - InstacartMediumSoftware EngineerCompute delivery wait times
This question evaluates competence in event-driven simulation, scheduling and queueing concepts, and algorithmic analysis by requiring computation of average customer waiting time for single and multiple shoppers.
Coding & AlgorithmsOnsite - InstacartEasySoftware EngineerEvaluate Ordered Variable Definitions with Addition and Subtraction
Evaluate ordered variable definitions and plus/minus expressions with an explicit directional grammar, while distinguishing assignment lookup from general equation solving.
Coding & AlgorithmsOnsite - InstacartMediumSoftware EngineerEvaluate arithmetic expression with precedence
Instacart software-engineer onsite coding question: implement an arithmetic expression evaluator for a string of non-negative integers, +, -, *, /, parentheses, and spaces. It tests operator precedence and associativity, unary minus, 64-bit intermediates, integer division truncating toward zero, and robust handling of invalid input via a two-stack, shunting-yard, or recursive-descent parser.
Coding & AlgorithmsOnsite - InstacartMediumSoftware EngineerEvaluate dependent variable expressions
This question evaluates a candidate's ability to parse and evaluate assignment expressions, resolve inter-variable dependencies, and detect cycles or unsolvable references.
Coding & AlgorithmsOnsite - InstacartMediumSoftware EngineerImplement bus route simulation features
This question evaluates a candidate's skills in stateful event-driven simulation, data-structure and algorithm design for capacity-constrained boarding and dropping logic, and statistical downsampling to preserve origin–destination demand distributions.
Coding & AlgorithmsOnsite - InstacartMediumSoftware EngineerImplement matrix-indexing and expression resolver
This question evaluates a candidate's ability to parse structured text files, perform matrix indexing with a nonstandard origin convention, reconstruct data across multiple blocks, and resolve symbolic variable expressions and dependencies for arithmetic evaluation in the Coding & Algorithms domain.
Coding & AlgorithmsOnsite
Google
Grammarly
Harvey
HubSpot
Hudson River Trading
Instacart