Given a graph represented by G(V, E) where V is the vertices and E represents the edges, we can do a Depth First Search Algorithm (DFS) on any node/vertex. The DFS will mark the current node visited and visit the node using using the (*visit) function (C++ function pointer), and recursively call itself with the connected edges.

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void traverseDepthFirstSearch(int node, void(*visit)(int)) {
  link t;
  (*visit)(k);
  visited[k] = 1; // mark the node as visited
  for (t = adj[k]; t != NULL; t = t->next) {
     if (!visited[t->v]) { // avoid cycle
         traverseDepthFirstSearch(t->v, visit);
     }
  }
}

void traverseDepthFirstSearch(int node, void(*visit)(int)) {
  link t;
  (*visit)(k);
  visited[k] = 1; // mark the node as visited
  for (t = adj[k]; t != NULL; t = t->next) {
     if (!visited[t->v]) { // avoid cycle
         traverseDepthFirstSearch(t->v, visit);
     }
  }
}

three-nodes

The algorithimic complexity is O(N) where N is the number of nodes connected to the given vertex. The space complexity is also O(N).

–EOF (The Ultimate Computing & Technology Blog) —