private static void StrongConnect(Vertex firstVertex)
{
Stack<Vertex> stack = new Stack<Vertex>();
stack.Push(firstVertex);
while (stack.Count > 0) {
Vertex v = stack.Pop();
v.index = index;
v.lowlink = index;
index++;
S.Push(v);
foreach (Vertex w in v.Adj) {
if (w.index < 0) {
StrongConnect(w);
v.lowlink = Math.Min(v.lowlink, w.lowlink);
}
else if (S.Contains(w)) {
v.lowlink = Math.Min(v.lowlink, w.index);
}
}
if (v.lowlink == v.index) {
var scc = new List<Vertex>();
Vertex w;
do {
w = S.Pop();
scc.Add(w);
} while (v != w);
_stronglyConnectedComponents.Add(scc);
}
}
}
public DTuple Prog(StrategySet rho, Vertex v, Vertex w)
{
var rho_w = rho[w];
var ret = new DTuple(rho_w.Count);
if (v.PriorityEven) {
// return the least m >= (up to p(v)) rho
// easily constructed by copying values up to p(v) and padding with 0
if (rho_w.IsTop) ret = MTop;
else for (int i = 0; i < v.Priority; i++)
ret[i] = rho_w[i];
}
else {
// return the least m > (up to p(v)) rho[w]
// constructed by taking the first elem before p(v) that can be incremented, MTop otherwise
for (int i = v.Priority; i >= 0; i--) {
if (rho_w[i] < MMaxEven[i]) {
ret[i] = rho_w[i] + 1;
// leave stuff in front same as rho_w
for (int j = 0; j < i; j++)
ret[j] = rho_w[j];
// and set remainder to 0
for (int j = i + 1; j < d; j++)
ret[j] = 0;
break;
}
else if (i == 0) // nothing could be incremented
ret = MTop;
else // copy this val, try to incr. next
ret[i] = rho_w[i];
}
}
return ret;
}
static void tarjan_iter(Vertex u, ref int index)
{
u.index = index;
u.lowlink = index;
index++;
u.vindex = 0;
_tarStack.Push(u);
u.caller = null; //Equivalent to the node from which the recursive call would spawn.
_onStack[u] = true;
Vertex last = u;
while (true) {
if (last.vindex < last.Adj.Count) { //Equivalent to the check in the for-loop in the recursive version
Vertex w = last.Adj[last.vindex];
last.vindex++; //Equivalent to incrementing the iterator in the for-loop in the recursive version
if (w.index == -1) {
w.caller = last;
w.vindex = 0;
w.index = index;
w.lowlink = index;
index++;
_tarStack.Push(w);
_onStack[w] = true;
last = w;
}
else if (_onStack[w] == true) {
last.lowlink = Math.Min(last.lowlink, w.index);
}
}
else { //Equivalent to the nodeSet iterator pointing to end()
if (last.lowlink == last.index) {
Vertex top = _tarStack.Pop();
var scc = new List<Vertex>() { top };
top.SCC = scc;
_onStack[top] = false;
int size = 1;
while (top.Id != last.Id) {
top = _tarStack.Pop();
top.SCC = scc;
scc.Add(top);
_onStack[top] = false;
size++;
}
_sccs.Add(scc);
}
Vertex newLast = last.caller; //Go up one recursive call
if (newLast != null) {
newLast.lowlink = Math.Min(newLast.lowlink, last.lowlink);
last = newLast;
}
else {
//We've seen all the nodes
break;
}
}
}
}
public Vertex GetV(int id)
{
var v = V[id];
if (v == null) {
v = new Vertex(id);
V[id] = v;
}
return v;
}
public Edge(Vertex from, Vertex to)
{
From = from;
To = to;
}
private void Lift(Vertex v, StrategySet rho)
{
var ps = v.Adj.Select(w => Prog(rho, v, w)).OrderBy(d => d);
rho[v] = v.OwnerEven ? ps.First() : ps.Last();
}
