//返回一个图的副本，但将其中所有边的方向反转
public Digraph Reverse()
{
var r = new Digraph(V);
for (int v = 0; v < V; v++)
{
foreach (var w in adj[v])
{
r.AddEdge(w, v);
}
}
return(r);
}
public SymbolGraph(string stream, char sp)
{
dic = new Dictionary <string, int>();
using (var reader = new StreamReader(stream)) {
while (reader.Peek() > -1)
{
var a = reader.ReadLine().Split(sp);
for (int i = 0; i < a.Length; i++)
{
if (!dic.ContainsKey(a[i]))
{
dic.Add(a[i], dic.Count);
}
}
}
keys = new string[dic.Count];
foreach (var item in dic)
{
keys[item.Value] = item.Key;
}
G = new Graph(dic.Count);
DirG = new Digraph(dic.Count);
reader.BaseStream.Seek(0, SeekOrigin.Begin);
while (reader.Peek() > -1)
{
var a = reader.ReadLine().Split(sp);
var v = dic[a[0]];
for (int i = 1; i < a.Length; i++)
{
G.AddEdge(v, dic[a[i]]);
DirG.AddEdge(v, dic[a[i]]);
}
}
}
}
