bayram's blog

Can anyone solve this problem?
By bayram, 12 years ago, In English

Give an algorithm that determines whether or not a given undirected graph G =(V,E) contains a cycle. Your algorithm should run in O(V) time, independent of |E|.

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12 years ago, # |
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Yes, they can

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    12 years ago, # ^ |
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    To be serious, the algorithm you know using dfs should work in O(V) time. Because until you find a cycle you will try only edges of the tree, so that is O(V).

    Another approach is |E| >= |V| => contains cycle, else O(E) = O(V), so you can do simple algorithm, too.

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12 years ago, # |
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Have you tried to google it?

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12 years ago, # |
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If |E| >= |V| graph has a cycle. else you can use dfs. It would be in O(V).

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12 years ago, # |
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Thanks everybody!

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