Topic
Coding & Algorithms interview questions
3276 Coding & Algorithms questions from 366 companies, with hints, runnable code and solution walkthroughs.
273 easy2539 medium464 hard
Coding & Algorithms interview questions by the numbers
Last updated
Katkat has 3,276 Coding & Algorithms interview questions from 366 companies; the most come from Amazon (7%), Meta (7%) and Google (6%). By difficulty: 8% easy, 78% medium and 14% hard. The most common round is Technical Screen (52%). Frequent concepts include Algorithms, Data Structures, Arrays and Greedy.
Companies (366)
Difficulty
- Easy8% · 273
- Medium78% · 2539
- Hard14% · 464
Interview rounds
- Technical Screen52% · 1706
- Onsite33% · 1080
- Online Assessment13% · 427
- HR Screen1% · 37
- Other1% · 26
Roles
- Software Engineer80% · 2629
- Machine Learning Engineer8% · 253
- Data Scientist7% · 241
- Data Engineer1% · 45
- Backend Engineer1% · 26
Frequent concepts
- Algorithms9% · 302
- Data Structures7% · 228
- Arrays5% · 176
- Greedy5% · 164
- Optimization5% · 151
- Hash Map4% · 124
Most mentioned in interview experiences
- 1.Solve Algorithmic Challenges in Online Coding Assessments15 reports
- 2.Solve LeetCode string and list problems11 reports
- 3.Solve sliding-window and heap problems8 reports
- 4.Implement LRU cache with O(1) ops7 reports
- 5.Implement and Analyze an LRU Query Cache6 reports
- 6.Determine Length of Longest Unique Substring5 reports
- 7.Match-3 Grid: Find Horizontal and Vertical Runs, Then Clear and Drop Cells5 reports
- 8.Design a single- and multi-threaded web crawler4 reports
- 9.Find an Exit in a URL Maze4 reports
- 10.Find deployable slots in a recurring week from allowed and freeze windows4 reports
Counted from 781 candidate interview experiences on Katkat. How we collect and count
Showing 2041–2070 of 3276 results
This question tests the ability to implement a deduplication algorithm that preserves the original relative order of elements while maintaining O(n) time and space complexity.
OktaFrontend EngineerCoding & AlgorithmsTechnical ScreenThis problem tests your ability to parse strings and apply conditional logic to validate technical data against specific constraints.
OktaSoftware EngineerCoding & AlgorithmsTechnical ScreenThis problem tests your ability to normalize strings into canonical forms using hashing or frequency counting to identify anagrams efficiently.
OkxSoftware EngineerCoding & AlgorithmsTechnical ScreenThis problem tests knowledge of thread synchronization using locks and condition variables to enforce a specific execution order between two concurrent processes.
OmnissaSoftware EngineerCoding & AlgorithmsOnsiteTests the ability to determine if a singly linked list is a palindrome in O(n) time and O(1) auxiliary space using two pointers and in-place list reversal.
OmnissaSoftware EngineerCoding & AlgorithmsOnsiteThis problem tests the ability to solve a search problem in O(N) time by utilizing the transitive and exclusionary properties of the 'knows' relationship to eliminate candidates.
OmnissaSoftware EngineerCoding & AlgorithmsOnsiteThis problem tests the ability to implement Kadane's algorithm to find the maximum sum of a contiguous subarray, specifically focusing on handling negative integers and maintaining optimal time and space complexity.
OmnissaSoftware EngineerCoding & AlgorithmsOnsiteThis problem tests your ability to handle recursive reduction patterns in a string using a stack-based approach to achieve linear time complexity.
OmnissaSoftware EngineerCoding & AlgorithmsOnsiteThis problem tests string manipulation, hash map usage, and state tracking to identify valid entry-to-exit sequences from an unordered stream of toll logs.
OnepaySoftware EngineerCoding & AlgorithmsTechnical ScreenTests dynamic programming on a 2D grid with extended state tracking to incorporate multi-step path history for score bonuses, path counting, and lexicographical path reconstruction.
OpenAISoftware EngineerCoding & AlgorithmsOnsiteDesign an in-memory aggregation system that tracks rolling window message counts and distinct active entities across chats with bounded memory and O(1) amortized operations.
OpenAISoftware EngineerCoding & AlgorithmsOnsiteTests proficiency in modern Android development with Kotlin and Jetpack Compose, focusing on unidirectional data flow (UDF), custom stateless composables, ViewModel state management, and asynchronous submission handling.
OpenAIAndroid EngineerCoding & AlgorithmsTechnical ScreenThis question evaluates frontend engineering skills including streaming data handling, incremental token-by-token rendering, asynchronous state management, and preserving UI responsiveness during long-running API streams.
OpenAIFrontend EngineerCoding & AlgorithmsTechnical ScreenPick a blue, green or red shirt for each of n days so that the total price is as low as possible while never buying the same color on two consecutive days, and return the chosen color sequence. It tests dynamic programming over a small state space and reconstruction of the optimal choices.
OpenAISoftware EngineerCoding & AlgorithmsTechnical ScreenChoose one of three paint colors for each car on an assembly line to minimize total cost, never repeating a color on consecutive cars, and return the exact color chosen for each car.
OpenAISoftware EngineerCoding & AlgorithmsTechnical ScreenThis problem tests your ability to model state propagation in a 2D grid using Breadth-First Search (BFS) to determine the time required for a dynamic condition to cover all reachable nodes.
OpenAISoftware EngineerCoding & AlgorithmsTechnical ScreenThis problem tests your ability to simulate state propagation across a grid over discrete time steps and determine the minimum number of interventions required to contain an infection.
OpenAISoftware EngineerCoding & AlgorithmsTechnical ScreenThis problem tests your ability to model a grid-based propagation process using Breadth-First Search (BFS), specifically handling multi-source initialization and obstacle avoidance.
OpenAISoftware EngineerCoding & AlgorithmsTechnical ScreenThis problem tests your ability to model a spreading process on a 2D grid using a multi-source Breadth-First Search (BFS) to determine the time required for a state to propagate across the entire space.
OpenAISoftware EngineerCoding & AlgorithmsOnsiteThis question evaluates understanding of IPv4 addressing, binary/bitwise manipulation, and the ability to summarize consecutive address ranges into minimal CIDR blocks, and belongs to the Coding & Algorithms domain for backend engineering roles.
OpenAIBackend EngineerCoding & AlgorithmsTechnical ScreenDetermine the number of connected components in an undirected graph represented as an adjacency matrix using graph traversal or disjoint set union.
OpenAISoftware EngineerCoding & AlgorithmsTechnical ScreenCount the ordered routes through a town's road network that visit exactly one shop of each of four types, where consecutive shops must share a direct road and a route and its reverse count separately. Tests graph modeling, path enumeration under type constraints and careful counting on small graphs.
OpenAISoftware EngineerCoding & AlgorithmsOnline AssessmentThis question evaluates a candidate's ability to design serializable, stateful abstractions in both in-memory and I/O-bound contexts. It tests understanding of iterator patterns, checkpoint-restore semantics, and test-driven development — competencies commonly assessed in engineering roles requiring systems thinking and API design rigor.
OpenAIMachine Learning EngineerCoding & AlgorithmsTechnical ScreenThis question evaluates competency in compiler and language design, covering grammar analysis, parsing algorithms (LL/LR/GLR/Earley/PEG), lexer and parser implementation, AST construction, error reporting and recovery, operator precedence and associativity, and analysis of time/space trade-offs.
OpenAISoftware EngineerCoding & AlgorithmsOnsiteThis question evaluates a candidate's ability to design persistent storage and in-memory data structures, covering serialization of arbitrary values, medium/interface design for byte-level persistence, crash-consistent flushing, error handling, and performance and complexity analysis.
OpenAISoftware EngineerCoding & AlgorithmsTechnical ScreenThis problem tests your ability to design an efficient data structure for text manipulation while implementing undo/redo history and a dynamic prefix-based autocomplete feature.
OpenAIMachine Learning EngineerCoding & AlgorithmsTechnical ScreenImplement an algorithm to find the earliest compatible software version while minimizing expensive compatibility-check API calls across partitioned version branches.
OpenAIMachine Learning EngineerCoding & AlgorithmsOnsiteThis question tests the ability to combine custom comparison logic with a binary search approach to identify the first transition point in a monotonic sequence.
OpenAIMachine Learning EngineerCoding & AlgorithmsOnsiteGiven one-way links in which every node has at most one outgoing link, follow the links from a start node and return the endpoint where the walk stops, or the last node visited before the walk would revisit a node. Tests single-successor graph traversal, visited-node bookkeeping and loop edge cases.
OpenAISoftware EngineerCoding & AlgorithmsTechnical ScreenThis question evaluates combinatorial reasoning and constructive algorithm design for generating constrained assignment schedules, including ensuring each human appears a minimum number of times, preventing duplicate human-task pairs, and managing valid ID ranges.
OpenAISoftware EngineerCoding & AlgorithmsTechnical Screen