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CPSPC 2010 Sailor
By zscoder, history, 9 years ago, In English

I was trying to solve this problem.

I could only figure out the naive solution. (DFS from each vertex) I think I have encountered similar problems before but I couldn't solve them either. How do I solve this kind of problem?

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9 years ago, # |
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Is there an English problem statement?

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    9 years ago, # ^ |
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    Oops, sorry I uploaded the wrong version. The link is updated now.

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9 years ago, # |
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Auto comment: topic has been updated by zscoder (previous revision, new revision, compare).

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9 years ago, # |
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The problem isn't that hard.

My idea is to compress the graph into strongly connected components. Then the new graph will be DAG. Lets call a LEAF every vertex with 0 outcoming edges. The value will be equal to the minimal size of a leaf (number of vertexes in leaf). This can be simply solved just by finding the leaves.

Overall complexity: O(N+M).

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    9 years ago, # ^ |
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    I see. I was thinking of SCC but didn't know how to proceed. I never used the trick of compressing SCCs into single vertices before.

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