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asked in Algorithms by Boss (6k points)   | 89 views

If i remove edge b/w B and E the graph is acyclic.

then apply DFS starts from vertex A.


It results two back edges D-C and E-B.

most cases it results only one back edge and in certain case like above it results two also.

Hence it results multiple back edges.

bt d-c is nt back edge it is cross edge
If some node is previously visited and we visit that node again then that edge is the back edge.

i missed it

Once u refer Coreman text book for DFS traversal,then u can easily understand.

parent node time intervals are u/v

and child is x/y then backside lies in b/w parent.i.e)u<=x<=y<=v   // condition for back edges.

so,whats the answer ..single or multiple??

1 Answer

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here is a result given in cormen book.....
A directed graph G is acyclic iff depth first search of G yields no back edges
i think b is correct

answered by Veteran (10.6k points)  

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