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Software Engineer 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 4051–4080 of 5874 results
- OpenAIMediumSoftware EngineerImplement in-memory KV store with serialization
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.
Coding & AlgorithmsTechnical Screen - OpenAIHardSoftware EngineerImplement malloc and free over Fixed Memory, Then Make Both Logarithmic
Implement malloc and free for a fixed range of memory in Python, first with a simple list of blocks and then with logarithmic-time operations backed by a third-party sorted container. It tests block splitting and merging, choosing ordered indexes for allocation and neighbor lookup, and keeping parallel structures consistent.
Software Engineering FundamentalsTechnical Screen - OpenAIMediumSoftware EngineerImplement node messaging and path discovery
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.
Coding & AlgorithmsTechnical Screen - OpenAIMediumSoftware EngineerImplement persistent key-value store
This question evaluates competency in implementing an in-memory key-value store with persistence, covering concepts such as serialization, durability, data structure management, and basic I/O handling.
Coding & AlgorithmsTechnical Screen - OpenAIHardSoftware EngineerImplement type AST and infer generics
This problem tests your ability to design a recursive data structure for an abstract syntax tree and implement a unification-based type inference engine for a simple functional language.
Coding & AlgorithmsTechnical ScreenASTType InferenceRecursion - OpenAIHardSoftware EngineerIn-Memory Key-Value Store with Crash Recovery from a Log and Concurrent Access
Implement an in-memory key-value store, make it recover from a log file after a crash, including a half-written final record, and make it correct and fast under many concurrent threads. It tests write-ahead logging, crash consistency, compaction, and lock design with group commit.
Software Engineering FundamentalsOnsite - OpenAIHardSoftware EngineerIndexed Vector as a Linked List with Checkpoints Every k Nodes
Implement an indexed dynamic sequence of strings, in the sense of an array list, that supports inserting at a position and reading by position. Starting from a plain singly linked list, build a linked list with a checkpoint every k nodes so reads cost O(k), and keep the checkpoints correct as insertions shift positions.
Software Engineering FundamentalsOnsite - OpenAIMediumSoftware EngineerInfection Spread Simulation with Death Threshold
Implement a cellular automaton simulating epidemic spread on a 2D grid with simultaneous infection and mortality transitions until convergence.
Coding & AlgorithmsTechnical Screenmatrixsimulationbreadth-first-search - OpenAIHardSoftware EngineerKey-Value Store Persistence: Length-Prefixed Bytes, Size-Capped Chunks, Thread Safety
A three-part key-value store exercise: serialize keys, values and their lengths into bytes and persist them on shutdown, split the saved data into chunks of a given maximum size, and discuss making the existing code safe for multithreaded use. It tests byte-level encoding, correct restore and concurrency reasoning.
Software Engineering FundamentalsTechnical Screen - OpenAIHardSoftware EngineerLab Robot Job Dispatcher with Backoff, Quarantine and Prereqs
Implement an in-memory job dispatcher where failed jobs wait out a per-job backoff, keep their original queue position, and get quarantined after repeated failures, then add prerequisite jobs with cascading quarantine. Tests state modeling, dual-heap scheduling, and online topological ordering.
Software Engineering FundamentalsTechnical Screenheapschedulingstate-machine - OpenAIHardSoftware EngineerLead Through Technical Difficulty and Project Conflict
This question evaluates your ability to provide engineering leadership through severe technical uncertainty, resolve architectural or project disagreements constructively, and deliver measurable impact under high expectations.
Behavioral & LeadershipHR ScreenLeadershipConflict ResolutionTrade-off Analysis - OpenAIMediumSoftware EngineerLease-Based Job Queue for Flaky Render Workers
Build an in-process job queue that hands out time-limited leases. A job is never lost when a worker crashes, hangs or fails, and jobs that always fail are dead-lettered after a retry limit. Tests state machines, fencing tokens, thread safety and clock-injected tests.
Software Engineering FundamentalsTechnical Screenconcurrencyqueuesfault-tolerance - OpenAIHardSoftware EngineerLeftmost-Fit Memory Allocator: Allocate Consecutive Units and Free by Owner
Simulate a memory allocator over n units: each allocation takes the leftmost run of consecutive free units for an owner, and each free releases all of that owner's units. Return the result of every operation. It tests interval bookkeeping and logarithmic-time search for free runs at up to 100,000 operations.
Coding & AlgorithmsOnsite - OpenAIHardSoftware EngineerLeftmost-Fit Theater Row Booking With Bulk Cancellation by Group
Simulate booking a single theater row of n seats, where each booking takes the leftmost block of consecutive free seats for a group and a cancellation releases every seat that group currently holds anywhere in the row. Tests augmented-interval bookkeeping and logarithmic-time search for the best free run.
Coding & AlgorithmsOnsitesegment-treeintervalssimulation - OpenAIMediumSoftware EngineerManage GPU Credits with Expiration
This question evaluates data-structure design and algorithmic reasoning for time-based resource accounting, including handling expiring credits and out-of-order operations while maintaining efficient (logarithmic) performance constraints.
Coding & AlgorithmsTechnical Screen - OpenAIMediumSoftware EngineerMerge overlapping intervals
This question evaluates algorithmic problem-solving skills focused on interval manipulation, sorting and merging logic, and time/space complexity analysis within the Coding & Algorithms domain, emphasizing practical application.
Coding & AlgorithmsTechnical Screen - OpenAIHardSoftware EngineerMicroorganism Eating Simulation: Largest Survivor After Left-to-Right Rounds
Simulate a row of microorganisms in which each one may eat a strictly smaller neighbor from a different family, with rounds resolved from left to right, and report the family and size of the largest survivor at equilibrium. It tests precise rule-following, list mutation during iteration, and careful per-round bookkeeping.
Coding & AlgorithmsOnline Assessment - OpenAIMediumSoftware EngineerMinimize deaths in spreading plant infection
This problem tests your ability to simulate a state-based grid propagation and optimize intervention timing using either greedy or dynamic programming approaches.
Coding & AlgorithmsTechnical ScreenSimulationBFSGrid - OpenAIHardSoftware EngineerModel particle hits on a screen
This question evaluates geometric reasoning and probability theory skills, specifically transformation of random variables and derivation of CDF/PDF from angular sampling, together with practical competence in Monte Carlo simulation and interpretation of numerical and visualization artifacts; domain: Software Engineering Fundamentals.
Software Engineering FundamentalsOnsite - OpenAIMediumSoftware EngineerMonitor Devices Over an Unreliable Network
Design an edge-to-cloud device monitoring system that accurately tracks device health and liveness across flaky, high-latency networks without falsely reporting absolute state.
System DesignOnsitesystem-designdistributed-systemsiot - OpenAIMediumSoftware EngineerOptimize C++ Performance with Provided Concurrency
This question evaluates a developer's skills in C++ performance engineering and concurrent systems, covering profiling, bottleneck identification (e.g., cache locality and lock contention), and code-level performance reasoning to improve throughput and latency.
Coding & AlgorithmsTechnical Screen - OpenAIMediumSoftware EngineerOrder Recipe Prep Steps Into the Smallest Valid Sequence
Return a deterministic, lexicographically smallest valid ordering of named prep steps with dependency constraints, correctly including steps with no prerequisites and steps unconnected to any dependency.
Coding & AlgorithmsTechnical Screentopological-sortgraphsheap - OpenAIMediumSoftware EngineerOrder Tasks with Dependencies Using a Deterministic Topological Sort
Tests deterministic topological sorting of a directed acyclic graph using Kahn's algorithm and a priority queue to guarantee lexicographical tie-breaking.
Coding & AlgorithmsTechnical Screengraphtopological-sortheap - OpenAIMediumSoftware EngineerParse and build binary data in Python
This question evaluates proficiency in binary data handling and serialization/deserialization in Python, including little-endian integer encoding, length-prefixed payloads, robust error handling for short reads and invalid lengths, and testability and performance considerations.
Data Manipulation (SQL/Python)Technical Screen - OpenAIHardSoftware EngineerPlant Infection Grid Simulation: Days to Stabilize, Immune Plants, Expiring Immunity
A progressive grid simulation: infection spreads daily between adjacent plants, and you compute how many days the garden takes to stabilize, then add permanently immune plants and immunity that expires after a countdown. It tests multi-source breadth-first search, Dijkstra-style waiting times and precise day counting.
Software Engineering FundamentalsOnsite - OpenAIHardSoftware EngineerPrevent Duplicate Request Processing
This System Design question evaluates understanding of idempotency, request deduplication, client- and server-side reliability mechanisms, and concurrency control in distributed systems.
System DesignHR Screen - OpenAIHardSoftware EngineerPrint Shop Job Queue: Retries, a Poison Queue and Job Prerequisites
Implement an in-memory job queue for a print shop where workers reserve, complete, or fail jobs, failed jobs retry up to a limit before landing in a poison queue, and a second part adds job prerequisites with cascading failure.
Software Engineering FundamentalsTechnical Screenqueuesstate-machinesretries - OpenAIMediumSoftware EngineerProject Deep Dive: Proving Technical Depth and Cross-Team Alignment
A behavioral project deep-dive question in which you present a past project while the interviewer asks how you aligned with other functional teams and with engineers on your own team, and repeatedly presses on where the technical depth lies. It tests structured storytelling, clear ownership, evidence-backed decisions and composure under challenge.
Behavioral & LeadershipOnsite - OpenAIMediumSoftware EngineerReactive Budget Notebook With Live Formulas and Cycle Rejection
Build a small reactive calculator where named variables hold integers or formulas that reference other variables, values stay correct as inputs change, and any definition that would create a circular dependency is rejected. Tests graph modeling, cache invalidation, cycle detection, and writing tests live.
Software Engineering FundamentalsOnsitedependency-graphcycle-detectioncaching - OpenAIHardSoftware EngineerReason About Binary Search with One-Call-Delayed Feedback
Implement and analyze binary search under a 1-step delayed-feedback protocol where each query response evaluates the previous guess.
Software Engineering FundamentalsTechnical Screenbinary-searchinteractivealgorithms
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