data-structures Graph traversals Depth First Search
Example
Depth First Traversal (or Search) for a graph is similar to Depth First Traversal of a tree. The only catch here is, unlike trees, graphs may contain cycles, so we may come to the same node again. To avoid processing a node more than once, we use a boolean visited array.
Below algorithm presents the steps for graph traversal using DFS:
Algorithm DFS(v);
Input: A vertex v in a graph
Output: A labeling of the edges as “discovery” edges and “backedges”
for each edge e incident on v do
if edge e is unexplored then
let w be the other endpoint of e
if vertex w is unexplored then
label e as a discovery edge
recursively call DFS(w)
else
label e as a backedge
