private boolean existsUnblockedSemiDirectedPath(Node from, Node to, List<Node> cond, Graph G) {
Queue<Node> Q = new LinkedList<Node>();
Set<Node> V = new HashSet<Node>();
Q.offer(from);
V.add(from);
while (!Q.isEmpty()) {
Node t = Q.remove();
if (t == to) return true;
for (Node u : G.getAdjacentNodes(t)) {
Edge edge = G.getEdge(t, u);
Node c = Edges.traverseSemiDirected(t, edge);
if (c == null) continue;
if (cond.contains(c)) continue;
if (c == to) return true;
if (!V.contains(c)) {
V.add(c);
Q.offer(c);
}
}
}
return false;
}
private static int shortestPath(Node n1, Node n2, Graph g) {
Queue<Node> Q = new ArrayDeque<Node>();
Map<Node, Node> V = new HashMap<Node, Node>();
Q.offer(n1);
V.put(n1, null);
while (!Q.isEmpty()) {
Node m = Q.poll();
if (V.containsKey(n2)) break;
for (Node p : g.getAdjacentNodes(m)) {
if (V.containsKey(p)) continue;
Q.offer(p);
V.put(p, m);
}
}
int s = 0;
do {
s++;
n2 = V.get(n2);
} while (n2 != null);
return s;
}