Decagon technical phone screen interview

Questions Decagon asks in this round 10

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  Count legal tic-tac-toe game sequencesCodingCount the legal game sequences on tic-tac-toe boards, including a 4x4 three-in-a-row variant, enumerating valid play orders with backtracking. Reported on 1point3acres' Decagon…

  Last asked Jul 2026Were you asked this too?
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  Recipe shopping cart with bulk discountsCodingModel a recipe shopping cart that prices ingredients with bulk discounts per ingredient. Reported on 1point3acres' Decagon bank; reconstructed in our own words.

  Last asked Jul 2026Were you asked this too?
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  Sliding window conversation scores with percentilesCodingTrack conversation quality scores in a sliding window and answer percentile queries over the current window. Reported on 1point3acres' Decagon bank; reconstructed in our own words.

  Last asked Apr 2026Were you asked this too?
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  Design an AI gatewayAI systemDesign a gateway that sits between a company's services and the language-model providers they call. Cover routing requests across providers and models, failover, rate limits and…

  Last asked Feb 2026Were you asked this too?
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  Send requests in batches of five and retry failures after a delayCodingDeliver a list of requests to an API that accepts at most five requests per call. Some requests in a call can fail; a failed request may be retried only after its own delay has…

  Last asked Sep 2026Were you asked this too?
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  Design a distributed job schedulerSystem designDesign a service that runs millions of scheduled and on-demand jobs (cron-like and one-off) reliably across a fleet of workers.

  Last asked Aug 2026Were you asked this too?
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  Cart with nested transactionsCodingImplement a cart whose updates run inside nestable transactions that commit or roll back as a unit. Reported on 1point3acres' Decagon bank; reconstructed in our own words.

  Last asked Jul 2026Were you asked this too?
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  Exclusive time of functionsCodingFrom function start and end logs, compute each function's exclusive execution time excluding nested calls. Reported on 1point3acres' Decagon bank; reconstructed in our own words.

  Last asked Mar 2026Were you asked this too?
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  Design a real-time AI voice agentAI systemDesign a system in which callers talk to an AI agent over the phone or in an app in real time: speech recognition, the language model, speech synthesis, keeping the response delay…

  Last asked Feb 2026Were you asked this too?
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  Sliding window average with updatesCodingMaintain a sliding window average over a stream with insert, average query and value updates, all efficient. Reported on 1point3acres' Decagon bank; reconstructed in our own words.

  Last asked Jan 2026Were you asked this too?