OpenAI technical screen: coding interview

Questions OpenAI asks in this round 38

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  Threshold infection spread on a gridCodingA lab tracks a disease across a rectangular field of cells. You are given an m x n grid where 0 is a healthy cell and 1 is an infected cell, and an integer threshold. Each day…

  Last asked Sep 2026Were you asked this too?
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  Memory allocator with malloc, free and coalescingCodingManage one arena of size bytes, addressed by offset from 0. You hand out and take back ranges of it, like malloc and free in C. Nothing is stored in the arena itself; track it in…

  Last asked Oct 2026Were you asked this too?
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  Find noisy annotators and retrain a classifier without themCodingA classifier is trained on labels from several human annotators, and some of them label carelessly. Find which annotators are unreliable, drop their labels, retrain, and show…

  Last asked Sep 2026Were you asked this too?
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  Toy language type inference with generics and tuplesCodingA small typed language has three kinds of type: - Primitives: int, float, char. - Generics: placeholders named T followed by a number (T1, T2, ...). A generic can stand for any…

  Last asked Sep 2026Were you asked this too?
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  Three-card showdown between two playersCodingDesign a two-player card game that uses a standard 52-card deck. Each card has a rank and a suit. From lowest to highest, the ranks are 2 3 4 5 6 7 8 9 10 J Q K A. The suits are C…

  Last asked Sep 2026Were you asked this too?
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  Entropy from logits, stable and then streamingCodingCompute the entropy of softmax(logits) for a vector of logits without overflow or underflow. Then the logits come in one by one: keep a fixed amount of state so the exact entropy…

  Last asked Jul 2026Were you asked this too?
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  Shard rebalancing with a per-key replica limitCodingOur key-value store spreads keys across shards. Each shard is given as a string "<id:<start:<end" and owns every integer key in the inclusive range start, end. Shards may overlap…

  Last asked Jun 2026Were you asked this too?
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  Restart strategy that cuts a solver's expected run timeCodingA model solves math problems, and the time a run needs to succeed follows a known, long-tailed distribution. You may stop a run and restart it at any time. Find a restart policy…

  Last asked May 2026Were you asked this too?
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  Resolve package versions from dependency constraintsCodingPackages have versions, and each version may require other packages within a version range. Parse the dependency specs, answer queries about which versions satisfy a constraint…

  Last asked May 2026Were you asked this too?
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  Lexicographically smallest topological orderCodingGiven tasks and the dependencies between them, return an order that runs every task after the tasks it depends on. When several tasks are ready at once, always pick the smallest…

  Last asked Sep 2026Were you asked this too?
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  Design a distributed rate limiterSystem designDesign a rate limiter that enforces a token-bucket limit per client across a fleet of servers. Cover where the limiter sits, where the bucket state lives (a shared store, local…

  Last asked May 2026Were you asked this too?
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  Merge intervalsCodingGiven a list of intervals (for example time ranges), merge every group of overlapping intervals and return the result in sorted order.

  Possibly retiredWere you asked this too?
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  Design a real-time multiplayer typing raceSystem designDesign an online typing race. Each race has 2 to 8 players. When the race starts, every player gets the same generated passage and types it; the first to finish the whole passage…

  Last asked Oct 2026Were you asked this too?
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  Follow one-way links to the endpoint or the last node before a loopCodingA network has nodes joined by one-way links, and each node links to at most one other node. Starting from a given node, follow the links and return the endpoint: the last node the…

  Last asked Oct 2026Were you asked this too?
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  Paint house: cheapest daily colors with no repeat on consecutive daysCodingFor the next n days a store sells blue, green and red shirts, and you get three cost arrays, one per color, giving each color's price on each day. You buy exactly one shirt every…

  Last asked Oct 2026Were you asked this too?
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  Design a metrics monitoring systemSystem designCollect metrics from every host and service, store them as time series, power dashboards over months of data, and alert when thresholds are crossed.

  Last asked Oct 2026Were you asked this too?
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  Hiring manager call: your past work, interests and latest projectBehavioralAfter the technical screens, a hiring manager asks about three things: what you have built so far, what you want to work on next, and the project you worked on most recently. Then…

  Last asked Sep 2026Were you asked this too?
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  Minimal reverse-mode autograd engineCodingWith PyTorch available, write the core of an automatic differentiation engine yourself. Build a small Tensor wrapper whose operations record how each result was computed, and a…

  Last asked Sep 2026Were you asked this too?
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  Rectangle board with remove-at-cell, batch remove and undoCodingBuild a RectangleBoard that holds axis-aligned rectangles on a grid of width columns and height rows. Cells use zero-indexed (x, y), where x is the column and y is the row. A…

  Last asked Aug 2026Were you asked this too?
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  Dependency-aware concurrent tool schedulerCodingBuild a scheduler that runs a set of tool calls concurrently while respecting their dependencies: a call starts only after every call it depends on has finished, and independent…

  Last asked Aug 2026Were you asked this too?
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  Engineering management fundamentals: one-on-ones, hiring and performanceBehavioralFor engineering manager candidates: explain your leadership philosophy and how you run one-on-ones, balance hands-on coding with managing, hire, grow people and handle…

  Last asked Aug 2026Were you asked this too?
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  Cross-entropy loss with masking and label smoothing in NumPyCodingImplement cross-entropy loss over a batch of logits in NumPy, stable for large values. Add a mask so padded positions do not count, then add label smoothing. Be ready to explain…

  Last asked Jul 2026Were you asked this too?
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  Max-score grid descent with limited two-row jumpsCodingYou are given an N x M grid of integers board. Rows and columns are numbered from 0, and a cell's value is the score you collect when you visit it. Values may be negative. A path…

  Last asked Jul 2026Were you asked this too?
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  Build a chat screen in an existing iOS codebaseCodingYou get an existing mobile app codebase and build a chat interface inside it: a list of messages and a field to send new ones, wired into the app's existing code. The round is…

  Last asked Jul 2026Were you asked this too?
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  Count connected friend groupsCodingGiven people and the friendships between them, count the friend groups: two people are in the same group when they are friends, directly or through a chain of friends. Solve it…

  Last asked Jul 2026Were you asked this too?
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  Design InstagramSystem designUsers post photos and videos, follow each other and scroll a feed; design upload, storage, feed generation and serving media worldwide.

  Last asked May 2026Were you asked this too?
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  Design the API layer of an Android app with MVVMSystem designDesign how an Android app talks to its backend API using the MVVM pattern: the layers from the network client up through repositories and view models to the screen, and what each…

  Last asked May 2026Were you asked this too?
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  Build a rating card in Jetpack ComposeCodingBuild a rating card component in Jetpack Compose: a card where the user picks a rating, which the UI shows and reports back to its caller. Keep its state handling clean and the…

  Last asked May 2026Were you asked this too?
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  Design per-user model usage quotas for a mobile appSystem designDesign how a mobile app enforces per-user quotas on model usage: how usage is counted, where the limit is enforced, what the app shows the user as they approach and reach it, and…

  Last asked May 2026Were you asked this too?
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  Build a chat input that renders a streamed AI replyCodingBuild a minimal ChatGPT-like page: a text box and a submit button, and below them the model's reply, rendered as it streams back from the API rather than all at once. Handle the…

  Last asked Apr 2026Were you asked this too?
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  Design an AI prompt playgroundAI systemDesign a web workspace where developers write prompts, run them against several models and settings, compare outputs side by side, and save and share versions.

  Last asked Apr 2026Were you asked this too?
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  Design Google DocsSystem designMany people edit the same document at once and see each other's changes and cursors live, with offline edits and full version history.

  Last asked Mar 2026Were you asked this too?
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  Text editor with undo and redoCodingBuild a small text editor supporting insert, delete, undo and redo with correct cursor behavior after each operation. Reported on 1point3acres' Notion bank; reconstructed in our…

  Last asked Mar 2026Were you asked this too?
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  Encode and decode strings with length prefixes and count codesCodingSerialize a list of arbitrary strings into one string and back without ambiguity. A second variant decodes a compact code where some letters are written as two digits with a…

  Last asked Oct 2025Were you asked this too?
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  C++ performance round with provided threading codeCodingA 60-minute coding round for performance-minded roles, held in C++. The focus is on core C++ performance, with a smaller part on concurrency; the threading components are…

  Possibly retiredWere you asked this too?
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  Design an ad marketplace between publishers and advertisersSystem designPublishers' pages request ads and advertisers bid to fill them. Design the marketplace: bidding and matching within a tight latency budget, serving the winning ad, and tracking…

  Possibly retiredWere you asked this too?
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  Debug a model whose accuracy drops after deploymentML designA model that looked fine offline loses accuracy suddenly once it is in production. Walk through how you would debug the whole pipeline step by step: where you look first, how you…

  Possibly retiredWere you asked this too?
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  Design a feed recommendation systemML designRank the items in each user's home feed so they engage more, choosing from millions of candidates within a couple of hundred milliseconds.

  Possibly retiredWere you asked this too?