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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
- Questions
- 546
- Companies
- 11
- Topics
- 8
- Languages
Showing 301–330 of 1080 results
- DatadogHardSoftware EngineerImplement Prefix Match Filter
This question evaluates understanding of prefix-based string matching, data structure design (hash-based sets and trie/prefix tree), and algorithmic competencies including efficient in-memory storage and deduplication of matches.
Coding & AlgorithmsOnsite - DatadogMediumSoftware EngineerImplement a Snowflake Query Client
This question evaluates API client design, asynchronous query lifecycle management, result retrieval, robust error handling, and secure credential handling for a cloud data warehouse.
Coding & AlgorithmsOnsite - DecagonMediumSoftware EngineerEnumerate 4x4 Tic-Tac-Toe Games
This question evaluates understanding of recursion and backtracking, exhaustive game-tree enumeration, and state representation for combinatorial game analysis.
Coding & AlgorithmsOnsite - DecagonMediumSoftware EngineerImplement CSAT tracking and call timing
This problem tests your ability to manage stateful data during event processing and calculate exclusive execution times from a stream of nested function logs.
Coding & AlgorithmsOnsiteStackSimulationData Structures - Deutsche BankHardSoftware EngineerSolve tree equality and valid parentheses
This problem set evaluates core skills in data structures and algorithmic reasoning, specifically binary tree structural equality and bracket-matching for strings, testing understanding of tree traversal, recursion, and stack-based parsing.
Coding & AlgorithmsOnsite - DiscordMediumSoftware EngineerImplement an asyncio-based chat server
This question tests practical knowledge of Python's asyncio library and concurrent programming by requiring the implementation of a TCP chat server. It evaluates a software engineer's ability to manage multiple simultaneous connections, handle resource cleanup, and apply event-driven concurrency patterns — core competencies commonly assessed in backend and systems-focused interviews.
Coding & AlgorithmsOnsite - DisneyMediumSoftware EngineerImplement an LRU cache
This problem tests your ability to design a cache that supports O(1) access, insertion, and eviction by combining two core data structures.
Coding & AlgorithmsOnsiteHash TableDoubly Linked ListDesign - DisneyMediumSoftware EngineerSolve grid shortest path with BFS
This question evaluates understanding of grid traversal and shortest-path graph search, including modeling a 2D grid with obstacles and reasoning about boundary and edge cases, within the Coding & Algorithms domain.
Coding & AlgorithmsOnsite - DocuSignEasySoftware EngineerCompress Consecutive Integer Ranges
Tests array manipulation, sorting, deduplication, and range-grouping logic to produce a compact string representation of consecutive numbers.
Coding & AlgorithmsOnsitearrayssortingstring - DocuSignMediumSoftware EngineerImplement a key-value CRUD store
This question evaluates understanding of core data structures, API design, complexity analysis, and edge-case handling for an in-memory key–value CRUD store, and falls under the Coding & Algorithms domain while testing both practical implementation skills and conceptual reasoning about time/space trade-offs.
Coding & AlgorithmsOnsite - DoorDashMediumSoftware EngineerCalculate Driver Payments
Implement a payout calculation system for delivery drivers by deduplicating order logs, merging overlapping active-time intervals, and computing base pay, delivery bonuses, and tips.
Coding & AlgorithmsOnsiteintervalssortinghash-table - DoorDashMediumSoftware EngineerCompute cart total with best promotion
This question evaluates numerical reasoning for monetary calculations, handling of multiple promotion types, precision and rounding considerations, and edge-case handling such as empty carts and clamping totals within the Coding & Algorithms domain.
Coding & AlgorithmsOnsite - DoorDashMediumSoftware EngineerCompute dasher pay with peak-hour query
This question tests the ability to handle overlapping time intervals and perform weighted calculations based on time-based pay multipliers.
Coding & AlgorithmsOnsiteAlgorithmsIntervalsData Processing - DoorDashMediumSoftware EngineerCompute nearest-exit distances in a grid
Compute nearest-exit distances in a grid 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 - DoorDashMediumSoftware EngineerDebug a driver assignment bug
This question evaluates debugging, root-cause analysis, unit/integration test design, observability, and system-resilience competencies within the Coding & Algorithms domain, emphasizing practical skills in reproducing failures, isolating defects, and implementing targeted fixes.
Coding & AlgorithmsOnsite - DoorDashMediumSoftware EngineerDebug and refactor a legacy module
This question evaluates debugging, refactoring, naming and exception handling, input validation, code structure, and concurrency-safety design skills within a legacy codebase, requiring both hands-on code changes and higher-level reasoning about immutability, confinement, synchronization, and concurrent data structures.
Coding & AlgorithmsOnsite - DoorDashMediumSoftware EngineerDebug using logs and allocate tasks
This question evaluates a candidate's skill in log-driven debugging, production incident investigation, and cross-functional task allocation, covering competencies such as structured and contextual logging, correlation identifiers, noise reduction, minimal reproducibility, feature-flagged isolation, triage coordination, hypothesis tracking, root-cause confirmation, regression prevention, and blameless postmortems. It is commonly asked to assess operational troubleshooting and teamwork under production uncertainty within the Coding & Algorithms category, testing practical application of debugging techniques alongside conceptual understanding of incident management and process-level coordination.
Coding & AlgorithmsOnsite - DoorDashMediumSoftware EngineerDesign a hierarchical path registry
Design a hierarchical path registry 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 - DoorDashMediumSoftware EngineerDesign dasher-to-order assignment algorithm
This question evaluates a candidate's skills in real-time algorithm design and systems thinking for dynamic matching and optimization, including scalability, time/space complexity analysis, and handling partial or delayed information.
Coding & AlgorithmsOnsite - DoorDashMediumSoftware EngineerDesign dynamic connectivity with alive nodes
This question evaluates understanding of dynamic graph data structures, connectivity algorithms, state management for node activation/deactivation, complexity analysis, and concurrent operation considerations.
Coding & AlgorithmsOnsite - DoorDashMediumSoftware EngineerFind Each Cell's Nearest Source
This question evaluates understanding of shortest-path computation and distance labeling in grid-based graphs, measuring competency in algorithmic problem solving and efficient traversal strategies.
Coding & AlgorithmsOnsite - DoorDashMediumMachine Learning EngineerFind closest value to a target in a BST
This question evaluates understanding of binary search tree properties and numeric approximation, measuring competence in tree traversal, comparison logic, and algorithmic efficiency under input-size constraints.
Coding & AlgorithmsOnsite - DoorDashHardSoftware EngineerFind longest common ordered restaurant list
This question evaluates a candidate's understanding of sequence algorithms, dynamic programming, and string/list manipulation by requiring computation of the longest common subsequence between two ordered lists of restaurant IDs.
Coding & AlgorithmsOnsite - DoorDashMediumSoftware EngineerFind the Minimum Delivery Processing Speed
This problem tests binary search on the answer space to find the minimum throughput capacity required to process a set of delivery orders within a fixed deadline.
Coding & AlgorithmsOnsiteBinary SearchOptimizationMath - DoorDashMediumSoftware EngineerFind the Minimum Parenthesis Deletions and Their Positions
This problem tests string manipulation, stack-based parsing, and greedy logic to identify the indices of parentheses that must be removed to transform a string into a valid sequence.
Coding & AlgorithmsOnsiteStringsStackGreedy - DoorDashMediumSoftware EngineerGenerate the next lexicographic array arrangement
This interview question evaluates algorithm design, data structures, correctness, complexity, edge cases, and implementation details in a realistic interview setting. A strong answer for Generate the next lexicographic array arrangement states assumptions, handles edge cases, explains trade-offs, and shows how to validate the result clearly.
Coding & AlgorithmsOnsite - DoorDashMediumSoftware EngineerIdentify members lacking specialty coverage
Identify members lacking specialty coverage 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 - DoorDashMediumSoftware EngineerImplement Timeout Refund Workflow
Design and implement a stateful, idempotent refund workflow manager that safely handles gateway timeouts, retries, and duplicate requests.
Coding & AlgorithmsOnsiteState MachineIdempotencySystem Design - DoorDashEasySoftware EngineerImplement a consistent hashing ring
This question evaluates understanding of consistent hashing, virtual nodes, deterministic hash functions, and data structure design for efficient key-to-server mapping and dynamic membership changes.
Coding & AlgorithmsOnsite - DoorDashMediumSoftware EngineerImplement a simple service with tests
Implement a simple service with tests 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
Datadog
Decagon
Discord
Disney
DocuSign
DoorDash