Perplexity technical screen or assessment interview

Round 2 of 7 · 13 questions reported

See the whole loop
Format
Online assessment or live coding (often CoderPad); problems come in parts, each adding a requirement to your code
They grade
Code that passes performance tests on large inputs, structure that survives new requirements, stated complexity
AI use
Assume no AI unless the recruiter says otherwise
Heads-up
Passing the visible tests is not enough: each part has its own tests and the hidden ones are stricter. Some screens use CoderPad's project mode, so leave time to learn how its tests run. Python is preferred; frontend loops can start with a longer TypeScript assessment.

Questions Perplexity asks in this round 13

  • In-memory file system with files and foldersCodingImplement an in-memory file system with path-based file and folder access, plus follow-ups on per-directory limits, duplicate names and identical contents. Covers the bank's vault…
    Last asked Oct 2026
  • Agent to-do list with task dependenciesCodingBuild the task tracker an AI agent uses to plan its work. The question comes in three parts. Each part builds on the one before, so keep earlier behavior working. A status is an…
    Last asked May 2026
  • Truncate model output at the first stop sequenceCodingImplement a function that returns the part of a string that comes before the earliest stop word. - text is any string. It may be empty. - stopwords is a list of non-empty strings…
    Possibly retired
  • Batching service around an embedding modelCodingPut a service around an embedding model: many callers send texts at once, the service groups them into batches for the model, returns each caller its vectors, and stops without…
    Possibly retired
  • Train and improve a binary classifier with scikit-learnCodingGiven a small labelled dataset, train a binary classifier with scikit-learn, report a sensible evaluation metric, and then improve it through feature handling, model choice or…
    Last asked Dec 2025
  • Reservoir sampling and a check that it is uniformCodingPick k items uniformly at random from a stream of unknown length in one pass and O(k) memory. Then write a simulation that tests whether your picks are close to uniform, and…
    Last asked Nov 2025
  • Stream deduplication with near-duplicate suppressionCodingPass through a stream of strings, keeping only the first copy of each. Then also drop strings that are near-duplicates of something already kept, above a similarity threshold, and…
    Last asked Nov 2025
  • Greedy and beam search decoding for a language modelCodingYou are writing the decoding step for a language model. Decoding turns the model's per-step scores into a sequence of token ids. Implement greedydecode(scores: listlistfloat) -…
    Possibly retired
  • Debug an overloaded Kubernetes clusterSystem designAn infrastructure round: a service running on Kubernetes is overloaded. Say which metrics you want to see first; the interviewer draws them for you, and you narrow the cause down…
    Possibly retired
  • Design Mint.comSystem designLink users' bank and card accounts, pull and categorize transactions daily, and show budgets and spending trends, keeping credentials safe.
    Possibly retired
  • LLM provider pool with failoverCodingWrite a client that sends completion requests to a pool of external LLM providers. It should be able to switch between providers, and when one goes down, move traffic to another…
    Possibly retired
  • GPU credit ledger with out-of-order eventsCodingBuild an in-memory ledger for GPU credits. Credit arrives as grants: each one has a unique id, an amount, and a time window in which it can be spent. Grants may overlap in time…
    Possibly retired