Consider the following graph,
Among the following sequences:
(I) a b e g h f (II) a b f e h g (III) a b f h g e (IV) a f g h b e
Which are depth first traversals of the above graph?
(A) I, II and IV only
(B) I and IV only
(C) II, III and IV only
(D) I, III and IV only
Explanation: We can check all DFSs for following properties.
In DFS, if a vertex 'v' is visited after 'u', then one of the following is true. 1) (u, v) is an edge. u / \ v w / / \ x y z 2) 'u' is a leaf node. w / \ x v / / \ u y z
In DFS, after visiting a node, we first recur for all unvisited children. If there are no unvisited children (u is leaf), then control goes back to parent and parent then visits next unvisited children.
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