Binary tree traversal non-recursive

Binary tree traversal non-recursive

Non-recursive binary tree traversal using the stack to achieve

• Since the order was to begin with, you should access node encountered, the next step should be downstream along the left branch of the tree.
• However, nodes and branches have not visited, and therefore needs to be recorded, and the node onto the stack.
• The null tree is traced back, remove the stack and a branch, like a binary tree as traversing it.

Code:

1 def preorder(t, proc):
2     s = Stack()
3     while t is not None or s not s.is_empty():
4         while t is not None:
5             proc(t.data)
6             if t.right:
7                 s.push(t.right)
8             t = t.left
9         t = s.pop()

 Traverse through the generator function

When writing program in Python, considering the data collection structure, always should think of iterators. The following is a non-recursive implementation visiting Binary Tree iterator:

1 def preorder(t):
2     s = Stack()
3     while t is not None or not s.is_empty():
4         while t is not None:
5             if t.right:
6                 s.push(t.right)
7             yield t.data
8             t = t.left
9         t = s.pop()