Pipeline task execution order — CodeArena

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Pipeline task execution order

Hard·Acceptance —·Asked at Amazon, Google

Given tasks and their upstream dependencies, return the order a scheduler should run them in. Detect cycles rather than looping forever.

Input schema

solve(tasks: list[str], deps: list[tuple[str, str]]) -> list[str] each dep is (upstream, downstream)

Example

tasks = ["load", "clean", "report"] deps = [("load", "clean"), ("clean", "report")] Output = ["load", "clean", "report"]

Constraints

Ties break on task name ascending, so the output is deterministic
A cycle raises ValueError naming one task in the cycle
A dependency on an unknown task raises KeyError
Up to 200,000 tasks and 1,000,000 edges

Topics

data modeling

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