How can we traverse all the nodes of a connected directed graph (as some roots may be inaccessible)?

Question

I wanted to find number of connected components in a directed graph but if we try using the general method that traverse nodes from 1 to n and for each node reach all its connected nodes and if we find any unreached node then we will take that node as another component.

.In this example , at least one of 4 or 7 can not be traversed as same (and will only be visited when started from there). So show me the algo that can consider it as the same component of a graph.

"consider it as the same component of a graph." what does "it" refer to in this sentence? — ravenspoint, Jul 21 '21 at 11:13
"it" refers to either 4 or 7 or both whichever part is not counted in that complete component — Adityabhan Singh Rathore, Jul 21 '21 at 12:08

score 0 · Answer 1 · answered Jul 21 '21 at 12:00

Nodes 4 and 7 are unreachable from each other, because their in-degrees are zero. That is, there are no directed edges point to them.

If you want to, for some reason, consider them "connected" because they have edges 'connecting' them to the rest of the graph even though the edges are directed the 'wrong' way, then you must modify the graph to replace all the directed edges with undirected and then run the "general method".

How can we traverse all the nodes of a connected directed graph (as some roots may be inaccessible)?

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