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Friendship Editing

USACO · 2025 · February · gold-3

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graph-algorithms

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sample trace

Friendship Editing: graph algorithms walkthrough

Friendship Editing: use the linked editorial?s graph algorithms idea on the published sample, then verify the displayed output.

Published input3 1 1 2 3 2 1 2 2 3 4 4 1 2 1 3 1 4 2 3modelAlgorithm ideaRepresent the task?s objects and connections as a graph, then use the editorial?s traversal or path method to obtain the requested property.task resultExpected output1 0 1
  1. 1

    Model

    Make one vertex per task object and add an edge for each permitted relationship.
  2. 2

    Process

    Traverse or relax the graph according to the task?s path or reachability rule.
  3. 3

    Read

    Use the reached set or path result to produce the requested output.
  4. 4

    Verify the sample

    Use the published sample output to check the result of this idea on the displayed input.
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