Perplexity coding interview

Round 3 of 7 · 5 questions reported

Length: 45 min
Format: Two live coding rounds
They grade: One implementation-heavy data-structures problem, one applied problem (streaming, ranking, state)
Heads-up: Problems are often small LLM-product simulations that grow part by part without breaking earlier tests: task dependencies, a byte tokenizer, streaming with stop sequences, provider failover, a credit ledger.

Questions Perplexity asks in this round 5

Speed up a byte tokenizer and estimate token countsCodingYou are given a slow but correct reference tokenizer over bytes. Explain precisely what it does, then write a faster version that returns identical output. Finally, estimate the…
Last asked Jan 2026
Infinite-scroll news feed in TypeScriptCodingUsing supplied mock data and fetch helpers, build a feed page of article cards in TypeScript that loads more as the reader scrolls. Show clean component structure, pagination…
Last asked Apr 2026
Temporal key-value store with point-in-time reads and restoreCodingBuild an in-memory key-value store that keeps every version of every key, so you can ask what a key held at any point in time. Implement the TemporalKVStore class: -…
Last asked Feb 2026
Find a way out of a restricted map zoneCodingGiven a starting latitude and longitude and a function that says whether a point is inside a premium zone, return a path that leaves the zone, or a nearby point outside it…
Possibly retired
Apply ordered token merges to a stringCodingMany language models read text as a list of token ids. In this scheme, every token after the single characters is built from two earlier tokens, and turning text into ids means…