help in the Donalds B. Johnson's algorithm, i cannot understand the pseudo code (PART II)

Question

i cannot understand a certain part of the paper published by Donald Johnson about finding cycles (Circuits) in a graph.

More specific i cannot understand what is the

Answer 1

I had sumbitted an edit request to @trashgod's code to fix the exception thrown in unblock(). Essentially, the algorithm states that the element w (which is not an index) is to be removed from the list. The code above used list.remove(w), which treats w as an index.

My edit request was rejected! Not sure why, because I have tested the above with my modification on a network of 20,000 nodes and 70,000 edges and it doesn't crash.

I have also modified Johnson's algorithm to be more adapted to undirected graphs. If anybody wants these modifications please contact me.

Below is my code for unblock().

private void unblock(int u) {
    blocked[u] = false;
    List list = b.get(u);
    int w;
    for (int iw=0; iw < list.size(); iw++) {
        w = Integer.valueOf(list.get(iw));
        //delete w from B(u);
        list.remove(iw);
        if (blocked[w]) {
            unblock(w);
        }
    }
}