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Coding & Algorithms interview questions

3276 Coding & Algorithms questions from 366 companies, with hints, runnable code and solution walkthroughs.

Questions3276

273 easy2539 medium464 hard

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Coding & Algorithms interview questions by the numbers

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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

Showing 2071–2100 of 3276 results

  • This question evaluates a candidate's ability to detect bugs and data-quality risks in a Python script, testing competencies in code review, reproducible randomization, idempotency, logging, duplicate-exposure safeguards, and safe experiment-assignment logic.

    OpenAIData ScientistCoding & AlgorithmsOnline Assessment
  • Design a fixed-size contiguous memory allocator supporting allocation and deallocation with immediate adjacent free-block coalescing.

    OpenAISoftware EngineerCoding & AlgorithmsTechnical Screen
  • This question evaluates data structures and algorithms competency, focusing on designing efficient in-memory counters and time-windowed event aggregation for (userId, chatId) pairs; it is categorized under Coding & Algorithms and has a practical implementation focus.

    OpenAISoftware EngineerCoding & AlgorithmsTechnical Screen
  • This question evaluates skills in graph-based modeling and temporal state simulation as well as the design and implementation of snapshot-capable directed graph data structures, covering competencies in propagation and state transitions (including immunity, recovery, and death), efficient snapshotting, querying, ranking, and diffing of follow relationships. It is commonly asked to assess algorithmic reasoning, correctness under edge cases, and complexity-aware implementation; the problem belongs to the Coding & Algorithms domain and tests both conceptual understanding of dynamic graph behavior and practical application-level implementation of data structures and immutable snapshots.

    OpenAISoftware EngineerCoding & AlgorithmsOnsite
  • This question evaluates a candidate's ability to design efficient stateful systems and algorithmic data structures for tracking per-tenant resource balances, including handling idempotency, negative balance policies, concurrency, and persistence.

    OpenAISoftware EngineerCoding & AlgorithmsTechnical Screen
  • Implement parsing, binary representation, arithmetic offsets, and canonical formatting for both IPv4 and IPv6 addresses and CIDR subnets.

    OpenAISoftware EngineerCoding & AlgorithmsOnsite
  • This problem tests your ability to manipulate IP address bit-representations and implement a custom iterator to traverse all addresses within a given CIDR block.

    OpenAISoftware EngineerCoding & AlgorithmsTechnical Screen
  • This question evaluates proficiency in designing scalable, time-versioned key-value data structures and in graph-based shortest-path planning for costed type conversions, assessing algorithmic thinking, complexity analysis, and robustness under large-scale constraints in the Coding & Algorithms domain.

    OpenAISoftware EngineerCoding & AlgorithmsTechnical Screen
  • This question evaluates skills in binary serialization and deserialization, data encoding and layout, type tagging, endianness, checksumming, versioning for forward/backward compatibility, and algorithmic efficiency and space usage for an in-memory key-value store; it falls under the Coding & Algorithms domain.

    OpenAISoftware EngineerCoding & AlgorithmsTechnical Screen
  • This problem tests your ability to navigate a social graph to implement a recommendation system using set operations and frequency counting.

    OpenAISoftware EngineerCoding & AlgorithmsTechnical Screen
  • This problem tests your ability to design a query-optimized representation for a directed graph, specifically focusing on efficient retrieval of multi-hop relationships and neighbor-based ranking.

    OpenAISoftware EngineerCoding & AlgorithmsTechnical Screen
  • This problem tests fundamental understanding of numerical stability in probability, memory-efficient buffering, and greedy combinatorial optimization.

    OpenAISoftware EngineerCoding & AlgorithmsHR Screen
  • Design an in-memory credit ledger that tracks GPU compute grants with expiration timestamps, consumes credits greedily by earliest expiration, and supports atomic deductions.

    OpenAISoftware EngineerCoding & AlgorithmsTechnical Screen
  • Simulate best-fit allocation across a contiguous address range using only primitive lists and scalar state. Support splitting, exact-pointer frees, double-free rejection, deterministic tie-breaking, and coalescing adjacent free blocks across up to 10,000 operations.

    OpenAISoftware EngineerCoding & AlgorithmsTechnical Screen
  • Implement a distributed token bucket rate limiter backed by a key-value store with optimistic concurrency control (CAS), handling clock skew, concurrent updates, and token replenishment.

    OpenAISoftware EngineerCoding & AlgorithmsTechnical Screen
  • This question evaluates understanding of concurrent resource management, advanced data structures for top-K and per-user queries, enforcement of caps and expirations, and algorithmic complexity guarantees while maintaining atomicity under concurrent operations.

    OpenAISoftware EngineerCoding & AlgorithmsTechnical Screen
  • This question evaluates understanding of memory allocator concepts including malloc/free semantics, contiguous allocation, fragmentation handling, coalescing of adjacent free blocks, pointer validation, and data-structure choices for efficient allocation.

    OpenAISoftware EngineerCoding & AlgorithmsTechnical Screen
  • This question evaluates competency in implementing robust serialization and in-memory data structures, covering binary format design, handling arbitrary bytes and Unicode, correctness across edge cases (empty state, large keys/values, overwrites, deletions), input validation and failure recovery, complexity analysis, and unit testing.

    OpenAISoftware EngineerCoding & AlgorithmsTechnical Screen
  • This problem tests your ability to handle IPv4 address arithmetic, bitwise operations, and the implementation of a stateful iterator that supports bidirectional traversal and range generation from CIDR notation.

    OpenAISoftware EngineerCoding & AlgorithmsOnsite
  • This problem tests your ability to manipulate 32-bit integers, understand bitwise operations, and implement a custom iterator for a contiguous range of IP addresses.

    OpenAISoftware EngineerCoding & AlgorithmsTechnical Screen
  • This question evaluates understanding of time-based resource accounting, design of data structures for expiring balances, atomic update semantics for concurrent operations, and algorithmic time/space complexity within the Coding & Algorithms domain.

    OpenAISoftware EngineerCoding & AlgorithmsTechnical Screen
  • This question evaluates implementation skills for an in-memory SQL-like table, focusing on data modeling with nested key-value structures, string handling, efficient lookups, and lexicographic sorting with tie-breaking.

    OpenAISoftware EngineerCoding & AlgorithmsOnsite
  • This question evaluates a candidate's ability to design reversible string encodings that handle arbitrary characters and edge cases, testing competency in string manipulation, data serialization, and robustness.

    OpenAISoftware EngineerCoding & AlgorithmsTechnical Screen
  • This question evaluates the ability to design efficient time-based data structures and algorithms for managing expiring credits with ordering and tie-breaking rules, testing competencies in event ordering, interval management, and retroactive update handling; it is in the Coding & Algorithms domain and emphasizes practical application of algorithmic and data-structure reasoning. It is commonly asked to verify correctness under out-of-order inserts and queries, to assess performance and complexity analysis for add/charge/get operations, and to require clear specification of time and space complexity for the proposed approach.

    OpenAISoftware EngineerCoding & AlgorithmsTechnical Screen
  • This problem tests your ability to design a versioned, immutable, or persistent data structure that supports efficient graph modifications and point-in-time snapshot queries.

    OpenAISoftware EngineerCoding & AlgorithmsTechnical Screen
  • This question evaluates design and implementation skills for mutable graph data structures with point-in-time snapshotting and recommendation ranking, testing knowledge of data structures, versioning, graph traversal, and algorithmic time/space complexity analysis.

    OpenAISoftware EngineerCoding & AlgorithmsTechnical Screen
  • This question evaluates a candidate's competency in data structures, algorithms, and systems-level thinking for implementing query processing in an in-memory database, including projection, predicate filtering, ordering, and index design.

    OpenAISoftware EngineerCoding & AlgorithmsTechnical Screen
  • This question evaluates skills in designing and implementing an in-memory key-value store with serialization, testing data structure design, API design (set/get/serialize/deserialize), serialization format selection, type fidelity for common Python types, and robust error handling.

    OpenAISoftware EngineerCoding & AlgorithmsTechnical Screen
  • This question evaluates understanding of data structures and algorithmic complexity in the context of designing a key-value in-memory database, and it falls under the Coding & Algorithms domain for a Machine Learning Engineer role while focusing on practical implementation skills.

    OpenAIMachine Learning EngineerCoding & AlgorithmsOnsite
  • This question evaluates skills in distributed systems and algorithms, including reliable message-passing between adjacent nodes, graph traversal and path discovery, fault-tolerant protocol design, and message/time complexity analysis.

    OpenAISoftware EngineerCoding & AlgorithmsTechnical Screen

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