Assign different colors to the different simple cycles /*, for example, by finding the articulation
    points [67]*/
(2) DFS traversal that starts at an arbitrary node and obeys the following rule: if a node is visited
    for the first time via a cycle with some color, then traverse all other differently colored links
    adjacent to before traversing the adjacent link of the same color. Enumerate the cactus leafs
     in the order in which they are first encountered in the DFS traversal.
Algorithm 8: Cactus-DFS .