duongquanghai08's blog

By duongquanghai08, history, 2 years ago, In English

shortest single cycle in an unweighted graph n<=1e6

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Is it a directed or an undirected graph?

If it's an undirected graph, you can construct a DFS Tree, and every back-edge defines a cycle

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I think this can help you

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orz dequy hai

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It can't be solved in better than $$$O(nm)$$$, where $$$m$$$ is the number of edges.

https://en.m.wikipedia.org/wiki/Girth_(graph_theory)#Computation