//static void Main()
// {
// Tree2 A = new Tree2("A");
// Tree2 B = new Tree2("B");
// Tree2 C = new Tree2("C");
// Tree2 D = new Tree2("D");
// Tree2 E = new Tree2("E");
// Tree2 F = new Tree2("F");
// Tree2 G = new Tree2("G");
// Tree2 H = new Tree2("H");
// Tree2 I = new Tree2("I");
// A.t.Add(B);
// A.t.Add(C);
// A.t.Add(D);
// A.t.Add(E);
// A.t.Add(F);
// A.t.Add(G);
// B.t.Add(H);
// B.t.Add(I);
// Forest fr = new Forest();
// fr.forestPre2(A);
// fr.forestPre(A);
// fr.forestPost(A);
// fr.forestPost2(A);
// }
/// <summary>
/// 树的森林的先序遍历，递归
/// </summary>
/// <param name="t"></param>
public void forestPre2(Tree2 t)
{
if (t == null)
{
return;
}
Console.WriteLine(t.node);
foreach (Tree2 tt in t.t)
{
forestPre2(tt);
}
}
/// <summary>
/// 森林的后序遍历，递归
/// </summary>
/// <param name="root"></param>
public void forestPost(Tree2 root)
{
if (root == null)
{
return;
}
foreach (Tree2 t in root.t)
{
forestPost(t);
}
Console.WriteLine(root.node);
}
/// <summary>
/// 树的森林的先序遍历，非递归
/// </summary>
/// <param name="root"></param>
public void forestPre(Tree2 root)
{
Tree2 tt = root;//根节点
Stack <Tree2> s = new Stack <Tree2>();
int[] whichChild = new int[200]; //访问到该节点的第几个子节点
int index = 0; //栈中元素索引
while (tt != null || s.Count > 0)
{
if (tt != null)
{
Console.Write(tt.node); //该节点输出
s.Push(tt); //该节点入栈
whichChild[index] = 0; //需要遍历该节点的子节点索引
if (tt.t.Count > 0) //有子节点
{
tt = tt.t[whichChild[index]];
whichChild[index]++;//需要访问该节点的下一个子节点
}
else
{
tt = null;
}
index++; //栈中下一个元素索引
}
else if (whichChild[index - 1] < s.Peek().t.Count) //找该节点的兄弟节点
{
tt = s.Peek().t[whichChild[index - 1]]; //获取兄弟节点
whichChild[index - 1]++; //该节点的下一个兄弟节点的索引
}
else
{
s.Pop();//删除该节点
index--;
tt = null;
}
}
}
/// <summary>
/// 森林的后序遍历，非递归，解释同上
/// </summary>
/// <param name="root"></param>
public void forestPost2(Tree2 root)
{
Tree2 tt = root;
Stack <Tree2> s = new Stack <Tree2>();
int[] whichChild = new int[200];
int index = 0;
while (tt != null || s.Count > 0)
{
if (tt != null)
{
s.Push(tt);
whichChild[index] = 0;
if (tt.t.Count > 0)
{
tt = tt.t[whichChild[index]];
whichChild[index]++;
}
else
{
tt = null;
}
index++;
}
else if (whichChild[index - 1] < s.Peek().t.Count)
{
tt = s.Peek().t[whichChild[index - 1]];
whichChild[index - 1]++;
}
else
{
tt = s.Pop();
Console.Write(tt.node);
index--;
tt = null;
}
}
}