private void strongConnect(SCCNode v, List<List<SCCNode>> sccs) {
// Set the depth index for v to the smallest unused index
v.index = index;
v.lowlink = index++;
stack.push(v);
stackSet.add(v);
// Consider successors of v
for (Node<SCCNode> n : v.getLinks()) {
SCCNode w = (SCCNode) n;
if (w.index == -1) {
// Successor w has not yet been visited; recurse on it
strongConnect(w, sccs);
v.lowlink = Math.min(v.lowlink, w.lowlink);
} else if (stackSet.contains(w)) {
// Successor w is in stack S and hence in the current SCC
v.lowlink = Math.min(v.lowlink, w.index);
}
}
// If v is a root node, pop the stack and generate an SCC
if (v.lowlink == v.index) {
List<SCCNode> SCC = new LinkedList<>();
SCCNode node = null;
do {
node = stack.pop();
stackSet.remove(node);
SCC.add(node);
} while (node != v);
if (SCC.size() > 1) sccs.add(SCC);
}
}
