Vertex |
Adj. List |

a | (b, c, d, e) |

b | (a, d, e) |

c | (a, f, g) |

d | (a, b, e) |

e | (a, b, d) |

f | (c, g) |

g | (c, f) |

- DFS of an undirected graph involves only two types of arcs.
- 1.
- Tree arcs.
- 2.
- Back arcs (there is no distinction between back arcs and forward arcs)
- Cross arcs also don't exist because given any two vertices, if there exists an arc between them, then one of them will be an ancestor and the other a descendant in the DFS. Thus all arcs that would have been cross arcs in the DFS of a digraph would become tree arcs in the case of an undirected graph.