How can we detect if a directed graph is cyclic? I thought using breadth first search, but I’m not sure. Any ideas?
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How can we detect if a directed graph is cyclic? I thought using breadth first search, but I’m not sure. Any ideas?
Usually depth-first search is used instead.
I don’t know if BFS is applicable easily.In DFS, a spanning tree is built in order of visiting. If a the ancestor of a node in the tree is visited (i.e. a back-edge is created), then we detect a cycle.
See http://www.cs.nyu.edu/courses/summer04/G22.1170-001/6a-Graphs-More.pdf for a more detailed explanation.