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; }