public AllPaths(DiGraph G, int s, int d)
{
this.S = s;
marked = new bool[G.Vnums()]; //instack = new bool[G.Vnums()];
stack = new Stack <int>(); path = new List <ArrayList>();
dfs(G, s, d);
}
private void dfs(DiGraph G, int v, int d)
{
if (!marked[v])
{
NodeList <int> w = G.adj[v];
stack.Push(w.val); //possible error？？
marked[w.val] = true;
}
foreach (int node in G.adj[v])
{
if (!marked[node])
{
stack.Push(node);
marked[node] = true;
if (node == d)
{
path.Add(new ArrayList());
foreach (int i in stack)
{
path[path.Count - 1].Add(i);
}
marked[stack.Pop()] = false;
continue;
}
dfs(G, node, d);
}
}
marked[stack.Pop()] = false;
}
private void dfs(DiGraph G, int v)
{
onStack[v] = true; marked[v] = true;
foreach (int w in G.adj[v])
{
if (this.hasCycle())
{
return;
}
else if (!marked[w])
{
edgeTo[w] = v;
dfs(G, w);
}
else if (onStack[w])
{
cycle = new Stack <int>();
for (int x = v; x != w; x = edgeTo[x])
{
cycle.Push(x);
}
cycle.Push(w);
cycle.Push(v);
}
onStack[v] = false;
}
}
private IEnumerable <int> order; //顶点的拓扑顺序
public Topological(DiGraph G)
{
DirectedCycle cyclefind = new DirectedCycle(G);
if (!cyclefind.hasCycle())
{
//这里是核心，使用了DFOrder 类 中的 逆后序方法
//一幅 有向无环图 的拓扑顺序 即为所有顶点的 逆后序排列
DFOrder dfs = new DFOrder(G);
order = dfs.ReversePost();
}
}
public DirectedDFS(DiGraph G, NodeList <int> sources) //链表sources 中的点 可达的所有点
{
marked = new bool[G.Vnums()];
while (sources != null)
{
if (!marked[sources.val])
{
dfs(G, sources.val);
}
sources = sources.next;
}
}
private bool[] onStack; //递归调用的栈 上的所有点
public DirectedCycle(DiGraph G)
{
marked = new bool[G.Vnums()];
edgeTo = new int[G.Vnums()];
onStack = new bool[G.Vnums()];
for (int v = 0; v < G.Vnums(); v++)
{
if (!marked[v])
{
dfs(G, v);
}
}
}
private void dfs(DiGraph G, int v)
{
pre.Enqueue(v);
marked[v] = true;
foreach (int w in G.adj[v])
{
if (!marked[w])
{
dfs(G, w);
}
post.Enqueue(v);
reversePost.Push(v);
}
}
private Stack <int> reversePost; //逆后序：.后，将顶点压入栈
public DFOrder(DiGraph G)
{
pre = new Queue <int>();
post = new Queue <int>();
reversePost = new Stack <int>();
marked = new bool[G.Vnums()];
for (int v = 0; v < G.Vnums(); v++)
{
if (!marked[v])
{
dfs(G, v);
}
}
}
private void dfs(DiGraph G, int v)
{
marked[v] = true;
NodeList <int> w = G.adj[v];
while (w != null)
{
if (!marked[w.val])
{
marked[w.val] = true;
dfs(G, w.val);
}
}
}
public DiGraph reverse() //反转，为了得到入边集合
{
DiGraph R = new DiGraph(V);
for (int v = 0; v < V; v++)
{
NodeList <int> w = adj[v];
while (w != null)
{
R.addEdge(w.val, v);
w = w.next;
}
}
return(R);
}
public DirectedDFS(DiGraph G, int s)
{
marked = new bool[G.Vnums()];
dfs(G, s);
}