static <Vertex extends BaseVertex, Edge extends BaseEdge<Vertex>> Vector<Edge> convertToDag(
BaseGraph<Vertex, Edge> graph) {
System.out.println("start convertToDag");
System.out.println(graph.getEdgesCount());
// copied from Dag.finACycle
byte[] mark = new byte[graph.getVerticesCount()];
BaseVertex[] V = graph.getVertexArray();
BaseVertex[] parent = new BaseVertex[mark.length];
BaseVertex[] root = new BaseVertex[mark.length];
Integer[] height = new Integer[mark.length];
LibraryUtils.falsifyVertexMarks(graph);
// start from one vertex and go to it's neighbors [BFS], continue until
// you meet a MARKed vertex
HashSet<Vertex> visitedVertices = new HashSet<Vertex>();
LinkedList<Vertex> bfsStack = new LinkedList<Vertex>();
Vertex cycleStart = null;
Vertex cycleEnd = null;
// visitedVertices.add(current);
int scan = 0;
int counter = 0;
Vertex current;
// perform a nonrecursive dfs
for (scan = 0; scan < V.length; scan++) {
Vertex u = (Vertex) V[scan];
if (!u.getMark()) {
/* Start a new search from u */
bfsStack.addFirst(u);
root[u.getId()] = u;
height[u.getId()] = 0;
while (!bfsStack.isEmpty()) {
Vertex v = bfsStack.removeFirst();
if (!v.getMark()) {
v.setMark(true);
counter++;
for (Vertex w : graph.getNeighbors(v))
if (!w.getMark()) {
bfsStack.push(w);
parent[w.getId()] = v;
root[w.getId()] = u;
height[w.getId()] = height[v.getId()] + 1;
}
}
}
}
}
Vector<Edge> ret = new Vector<Edge>();
// try to find backedges
for (Edge e : graph.edges()) {
int src = e.source.getId();
int trg = e.target.getId();
if (root[src] == root[trg] && height[src] > height[trg]) {
ret.add(e);
System.out.println(ret.size());
// cycleStart = e.target;
// cycleEnd = e.source;
//
//
// current = cycleEnd;
// LinkedList<Vertex> ret = new LinkedList<Vertex>();
// ret.addFirst(current);
// while (current != null && current != cycleStart) {
// current = (Vertex) parent[current.getId()];
// ret.addFirst(current);
// }
// if (current != null)
// return;
}
}
return ret;
}
