public AcyclicSP(DirectedWeightedEdgeGraph G, int s)
{
//从加权有向图中获取它的有向图，以供拓扑排序用
tmpG = new DirectGraph(G.GetV());
for (int v = 0; v < G.GetV(); v++)
{
foreach (var e in G.GetAdj(v))
{
int to = e.To();
tmpG.AddAdj(v, to);
}
}
int V = G.GetV();
edgeTo = new DirectedWeightedEdge[V];
distTo = new double[V];
for (int i = 0; i < V; i++)
{
distTo[i] = double.MaxValue;
}
distTo[s] = 0.0;
Topological top = new Topological(tmpG);
foreach (var v in top.Order)
{
relax(G, v);
}
}
public Topological(DirectGraph G)
{
DirectCycle cycle = new DirectCycle(G);
if (!cycle.hasCycle())
{
DFSOrder dfsOrder = new DFSOrder(G);
order = dfsOrder.ReversePost;
}
}
public DFSOrder(DirectGraph G)
: base(G)
{
reversePost = new Stack <int>();
for (int v = 0; v < G.GetV(); v++)
{
if (!marked[v])
{
Search(v);
}
}
}
public DirectCycle(DirectGraph _G)
: base(_G)
{
onStack = new bool[G.GetV()];
for (int t = 0; t < G.GetV(); t++)
{
if (!marked[t])
{
Search(t);
}
}
}
private int M;//状态数量,即正则表达式长度
/// <summary>
/// 根据给定的正则表达式构造NFA
/// </summary>
public NFA(string regexp)
{
Stack<int> ops = new Stack<int>();//用来保存左括号、或符号
re = regexp.ToCharArray();
M = re.Length;
G = new DirectGraph(M + 1);//有向图，保存每个点出发可以到达的点
for (int i = 0; i < M; i++)
{
int lp = i;
if (re[i] == '(' || re[i] == '|')//|的索引也要压入栈中，这样因为（的索引也压入了，可以遇到右括号时，（和|的索引都能知道，就能实现或跳转了
{
ops.Push(i);
}
else if (re[i] == ')')
{
List<int> orList = new List<int>();
while (ops.Count > 0)
{
int or = ops.Pop();
if (re[or] == '(')//找到|符号的上一个左括号的位置
{
lp = or;
break;
}
if (re[or] == '|') orList.Add(or);
}
foreach (var or in orList)
{
G.AddAdj(lp, or + 1);//把（和|后面的第一个字符相连
G.AddAdj(or, i);//把|和)相连
}
}
if (i < M - 1 && re[i + 1] == '*')//当前字符下一字符为闭包
{
G.AddAdj(lp, i + 1);//即B->*
G.AddAdj(i + 1, lp);//即*->B
}
if (re[i] == '(' || re[i] == '*' || re[i] == ')')//这些符号也都可以进入下一状态，但|不能直接进入下一状态。普通字符之间不需要进行连接，因为不是epsilon转换
{
G.AddAdj(i, i + 1);
}
}
}
public DFSOrder(DirectGraph G)
: base(G)
{
reversePost = new Stack<int>();
for (int v = 0; v < G.GetV(); v++)
{
if (!marked[v])
{
Search(v);
}
}
}
public Topological(DirectGraph G)
{
DirectCycle cycle = new DirectCycle(G);
if (!cycle.hasCycle())
{
DFSOrder dfsOrder = new DFSOrder(G);
order = dfsOrder.ReversePost;
}
}
public DirectCycle(DirectGraph _G)
: base(_G)
{
onStack = new bool[G.GetV()];
for (int t = 0; t < G.GetV(); t++)
{
if (!marked[t])
{
Search(t);
}
}
}
