二叉树的遍历(非递归)

Posted 2021-02-17 huayra

 1 //二叉树的先序遍历(非递归)
 2 public void PreOrderTraverse()
 3 {
 4     BiTNode p = this.root;
 5     Stack stack = new Stack(10000);
 6 
 7     while(!stack.isEmpty || p != null)
 8     if(p != null)
 9     {
10         if(p.rchild != null)
11         stack.push(p.rchild);
12         System.out.print(p.data + " ");
13         p = p.lchild;
14     }
15     else
16     {
17         p = stack.pop();
18     }
19 }
20 
21 //二叉树的中序遍历(非递归)
22 public void InOrderTraverse()
23 {
24     BiTNode p = this.root;
25     Stack stack = new Stack(10000);
26 
27     while(!stack.isEmpty() || p != null)
28     if(p != null)
29     {
30         stack.push(p);
31         p = p.child;
32     }
33     else
34     {
35         p = stack.pop();
36         System.out.print(p.data + " ");
37         p = p.lchild;
38     }
39 }

 1 //二叉树的后序遍历(非递归)
 2 public void PostOrderTraverse()
 3     {
 4         BiNode p = this.root;
 5         Stack stack = new Stack(10000);
 6         
 7         while(true)
 8         {
 9             if(p != null)
10             {
11                 if(p.count == 0)
12                 {
13                     stack.push(p);
14                     p = p.lchild;
15                 }
16                 else if(p.count == 1)
17                     p = p.rchild;
18                 else if(p.count == 2)
19                 {
20                     System.out.print(stack.pop().data + " ");
21                     if(!stack.isEmpty())
22                     {
23                         p = stack.getTop();
24                         p.count++;
25                     }
26                     else
27                         break;   //栈为空(根结点已出栈)
28                 }
29             }
30             else  //p = null 
31             {
32                 p = stack.getTop();
33                 p.count++;
34                 if(p.count == 1)
35                     p = p.rchild;
36                 else if(p.count == 2)
37                 {
38                     System.out.print(stack.pop().data + " ");
39                     if(!stack.isEmpty())
40                     {
41                         p = stack.getTop();
42                         p.count++;
43                     }
44                     else
45                         break;   //栈为空(根结点已出栈)
46                 }
47             }
48         }   //while
49     }