Game of Life on a grid too big for memoryCodingStarting from working Game of Life code, adapt it to a grid stored on disk that cannot be loaded at once, using given file helpers. Keep next-generation semantics exact, including…
Last asked Oct 2026
Applied Intuition
A recruiter call, a CoderPad coding screen and a call with the hiring manager (in either order), then an onsite of design and coding. Since mid-2026 many onsites pair a system design with a two- to three-hour build of it using Claude, followed by a presentation of the result.
- Merge overlapping collinear segments in the planeCodingSegments in 2D each carry an ordered list of points. Merge segments that lie on the same line and overlap, keeping every point, and take care with vertical segments and…Last asked Oct 2026
- Ingest MCAP driving logs and query them by timestampCodingBuild a small data service over recorded vehicle drives, with an AI coding assistant allowed. Each drive (a run) is stored as an MCAP file: timestamped messages on several topics…Last asked Oct 2026
- Walk through your career decisionsBehavioralExplain the main choices in your education and career: what alternatives you had, what constrained you, why you chose as you did, and how you judge those choices now. Connect them…Last asked Oct 2026
- Build a driving-log replay viewer with an AI assistantCodingIn two to three hours, with an AI coding assistant, build a web app that loads recorded autonomous-vehicle logs from cloud storage and plays them back as an interactive…Last asked Oct 2026
- Parse message definitions and compute their sizesCodingParse text definitions of message types made of typed fields, where a field can be another message type. Report each field's type and each message's total size from given…Last asked Sep 2026
- Locate vehicles with a square-region query APICodingAn API answers whether any vehicle lies inside a given square region. Use it to find every vehicle's location. Clarify the search bounds, how precise positions must be and how to…Last asked Sep 2026
- Design a real-time 3D playback system for recorded vehicle logsSystem designDesign a system that replays a recorded vehicle drive as an interactive 3D scene. A drive is a set of timestamped logs (sensor data, vehicle pose and similar) kept in object…Last asked Sep 2026
- Fixed-capacity circular bufferCodingImplement a generic FIFO buffer with a fixed capacity, allocated once up front, with constant-time push and pop. Discuss how to signal full and empty and how the buffer would be…Last asked Aug 2026
- Reassemble a stream of TLV messages in CCodingMessages arrive over a byte stream in type-length-value (TLV) form: a type, a length, then that many bytes of value. The stream is delivered in chunks of arbitrary size, so one…Last asked Aug 2026
- Evaluate variable definitions with forward references and cyclesCodingA list of assignments defines variables with arithmetic expressions that may use variables defined later. Evaluate them all, then report which ones are undefined because they…Last asked Aug 2026
- Recruiter screen: motivation, background and logisticsBehavioralA short first call with a recruiter: a few standard behavioral questions about your background and why you want the role, then timeline, location and compensation expectations…Last asked Aug 2026
- Step a set of moving vehicles until the first collisionCodingEach vehicle is a circle with a position, heading, constant speed and turn rate. Advance them in small fixed time steps and stop at the first time two of them touch, reporting…Last asked Jun 2026
- Key-value store with nested transaction rollbackCodingImplement an in-memory key-value store whose string keys map to string values. It supports transactions, and transactions can be nested. Implement the class KeyValueStore: -…Last asked May 2026
- Validate a parsed config against field descriptorsCodingGiven a parsed YAML or JSON document and a set of message descriptors that list each field's type and whether it is required or repeated, report every invalid field with the…Last asked Apr 2026
- Deterministic-order parallel reduction in CUDACodingWrite a parallel reduction on the GPU (for example a sum over a large float array) whose result does not depend on how threads happen to be scheduled: the additions must happen in…Last asked Apr 2026
- Single-threaded scheduler for one-shot, delayed and periodic tasksCodingBuild a scheduler that runs on a single thread and accepts three kinds of jobs: run once now, run once after a delay, and run every N units of time. Decide how the clock moves…Last asked Feb 2026
- Deduplicate files by size then content hashCodingWalk a directory tree and group files with identical content. Compare file sizes first so large files are hashed only when sizes collide, then hash the rest. Be ready to discuss…Last asked Feb 2026
- Find first and last position of an element in a sorted arrayCodingGiven an array of integers sorted in non-decreasing order and a target value, return the index of the first and the last occurrence of the target, or -1, -1 when it is absent. The…Last asked Feb 2026
- Intersection of two line segmentsCodingGiven two line segments in the plane, each by its two endpoints, decide whether they intersect and return the intersection point (or the overlapping piece when they are collinear…Last asked Feb 2026
- Compress a vertex list into unique vertices and indicesCodingTurn a list of vertex tuples into a list of unique vertices in first-seen order plus an index array that rebuilds the original list.Last asked Feb 2026
- Design a simulator that replays recorded left-turn scenariosSystem designDesign a simulator that takes recorded videos of real left turns and replays them as scenarios, so an autonomous-driving stack can be tested against what actually happened on the…Last asked Feb 2026
- Report timed-out simulations from start, ping and end eventsCodingSimulations send start, ping and end events with timestamps. After each new event, return the simulations whose last activity is now older than the timeout and that have not ended.Last asked Dec 2025
- Analyse vehicle speed readings from a JSON feedCodingFetch a JSON document of nested vehicle observations and find the fastest reading and the vehicle whose speed varied the most. Follow-ups add missing readings and legitimate…Last asked Nov 2025
- Project deep dive: present a project you ledBehavioralPresent a project you led in about 20 minutes: context, your role, the architecture, three hard trade-offs, metrics, cost and return, and what you would change. Then take 25…Last asked Nov 2025
- Debug a vision transformer notebookCodingA notebook trains a small vision transformer on handwritten digits but performs badly. Find and fix the implementation bugs, paying attention to details like masking and padding…Possibly retired
- Plan how you would hire for your teamBehavioralAs an engineering manager, walk through hiring for a team end to end: defining the role, finding candidates, designing the interviews, deciding, and closing offers. Explain what…Possibly retired
- Plan tasks across engineers and sprintsBehavioralAs an engineering manager, assign a backlog of tasks with deadlines to a few engineers over several sprints, respecting each engineer's focus area and available days. Explain the…Possibly retired
- Find the planted bugs in a small Transformer training scriptCodingA small Transformer, its training script and some tests are provided, with a few bugs hidden in them. Find and fix them so the loss goes down and the outputs are correct, and…Possibly retired
- Add a KV cache to GPT inferenceML designYou have a small GPT model with plain autoregressive generation that recomputes attention over the whole sequence for every new token. Add a key-value cache so each step only…Possibly retired
- Best meeting point on a gridCodingA grid marks several people's (or points') positions. Find the cell that minimizes the total distance to all of them. Start with a brute force (for example a BFS from each point)…Possibly retired
- Design a job schedulerSystem designDesign a service that runs jobs for other teams: jobs can run once, at a given time or on a recurring schedule. Cover how jobs are submitted and stored, how the scheduler finds…Possibly retired
- Shopping cart pricing with category couponsCodingA shopping cart holds items, each with a category and a price. A coupon names a category and gives a percentage or amount off, and it applies only when the cart meets its…Possibly retired
- What could put you at risk of a performance improvement plan?BehavioralA skip-level manager asks what about you or your work could put you at risk of a performance improvement plan (PIP). A good answer is honest about a real weakness or failure mode…Possibly retired