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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 2101–2130 of 3276 results
- 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 - 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 - OpenAIMediumMachine Learning EngineerInfer Generic Return Types
Implement a toy type-inference engine that unifies generic parameter types with concrete argument types and substitutes resolved type variables to determine the return type.
Coding & AlgorithmsOnsiterecursiontreetype-systems - 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 - 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 EngineerRebalance shard ranges under overlap limit
This problem tests interval manipulation and greedy optimization by requiring you to adjust a set of shard ranges so that no more than k ranges overlap at any integer point, while minimizing the number of boundaries moved.
Coding & AlgorithmsTechnical ScreenAlgorithmsSweep-LineIntervals - OpenAIHardSoftware EngineerRefactor a chat message processing function
This problem tests your ability to refactor procedural, error-prone code into a robust, extensible pipeline for parsing and managing chat message state.
Coding & AlgorithmsTechnical ScreenRefactoringString-ManipulationOOP - OpenAIHardSoftware EngineerResolve Short-Link Redirect Chains That May Loop
Follow single-target redirects from a start code and return the final code, or the last code before the walk would revisit one. Then answer many starts in linear total time. Tests visited-set bookkeeping and functional-graph structure.
Coding & AlgorithmsTechnical Screengraphsfunctional-graphcycle-detection - OpenAIMediumSoftware EngineerReturn the Lexicographically Smallest Topological Order
Implement a deterministic topological sort using a min-heap to return the lexicographically smallest ordering of a directed graph, or detect cycles and return an empty list.
Coding & AlgorithmsOnsitegraphtopological-sortheap - OpenAIHardSoftware EngineerRotate Couriers Daily at Minimum Total Cost
Choose one courier company per day so that no company works two days in a row and the total price is minimal, then return the schedule. Tests DP over a small state, path reconstruction, and the best/second-best trick for k options.
Coding & AlgorithmsTechnical Screendynamic-programmingreconstructionarrays - OpenAIHardMachine Learning EngineerSchedule Incremental Labeling Tasks
This problem tests the ability to design an incremental task scheduler that balances workload across a pool of annotators while maintaining fairness and deterministic state transitions.
Coding & AlgorithmsOnsiteHeapsSchedulingGreedy - OpenAIHardMachine Learning EngineerSearch Monster Battle Strategies
Design a search algorithm using state-space exploration to find the minimum number of turns required to defeat a boss given transient health, scripted boss attacks, and a single-use revive.
Coding & AlgorithmsOnsiteBreadth-First SearchState Space SearchGraph Algorithms - OpenAIHardMachine Learning EngineerSimulate Infection Spread on a Grid
Implement a discrete-time cellular automaton simulating epidemic spread on a 2D grid with multi-day infection states, immunity waning, and mortality rules.
Coding & AlgorithmsTechnical ScreenSimulationMatrixCellular Automata - OpenAIMediumMachine Learning EngineerSimulate Infection Spread with Immunity and Recovery
Implement a cellular automaton simulation modeling disease spread on a 2D grid with discrete cell states and timed recovery.
Coding & AlgorithmsTechnical ScreenGrid SimulationCellular AutomataBFS - OpenAIHardMachine Learning EngineerSimulate Plant Infection With Controlled Burning
This question evaluates a candidate's ability to implement discrete-time grid simulations with delayed state transitions, reason about simultaneous updates and neighborhood effects, and perform a limited combinatorial optimization (choosing one row or column) to minimize a global outcome.
Coding & AlgorithmsOnsite - OpenAIMediumMachine Learning EngineerSimulate Turn-Based Monster Battles
This problem tests your ability to design a stateful simulation engine that handles turn-based mechanics, complex status modifiers, and dynamic combat interactions.
Coding & AlgorithmsOnsiteSimulationState ManagementGame Logic - OpenAIEasySoftware EngineerSimulate a Turn-Based Two-Player Game
This problem tests your ability to design a robust state management system and implement validation logic for a rule-based game.
Coding & AlgorithmsTechnical ScreenState ManagementAPI DesignSimulation - OpenAIMediumSoftware EngineerSpreading Contagion on a Grid
Tests modeling multi-source breadth-first search (BFS) on a 2D grid to compute simultaneous state propagation across discrete time steps.
Coding & AlgorithmsTechnical Screenmulti-source-bfsgraphsmatrix - OpenAIHardMachine Learning EngineerStreaming Entropy with Numerical Stability
Implement an online, numerically stable algorithm to compute Shannon entropy over an unbounded stream of categorical tokens with O(1) updates.
Coding & AlgorithmsTechnical Screenstreamingmathnumerical-computing - OpenAIMediumMachine Learning EngineerTrack Expiring GPU Credits
Design an in-memory credit ledger to track expiring GPU compute credits, support priority consumption, and manage resource debt.
Coding & AlgorithmsOnsiteHeapDesignGreedy - OpendoorHardBackend EngineerExecute a TTL Key-Value Store with Transactions
This problem tests the implementation of an in-memory key-value store supporting TTL expiration, atomic transactions with rollback capabilities, and logical time-based validation.
Coding & AlgorithmsTechnical ScreenHashMapsTransactionsTTL - OptiverMediumSoftware EngineerBuild and Validate a Binary Tree from Parent-Child Pairs
This question evaluates understanding of tree and graph concepts, strict string parsing and validation, duplicate and cycle detection, and the construction of canonical S-expressions within the Coding & Algorithms category.
Coding & AlgorithmsOnline Assessment
OpenAI
Optiver