Pre-order to post-order traversal

Question

If the pre-order traversal of a binary search tree is 6, 2, 1, 4, 3, 7, 10, 9, 11, how to get the post-order traversal?

Answer 1

This is the code of preorder to postorder traversal in python. I am constructing a tree so you can find any type of traversal

def postorder(root):
    if root==None:
        return
    postorder(root.left)
    print(root.data,end=" ")
    postorder(root.right)

def preordertoposorder(a,n):
    root=Node(a[0])
    top=Node(0)
    temp=Node(0)
    temp=None
    stack=[]
    stack.append(root)
    for i in range(1,len(a)):
        while len(stack)!=0 and a[i]>stack[-1].data:
            temp=stack.pop()
        if temp!=None:
            temp.right=Node(a[i])
            stack.append(temp.right)
        else:
            stack[-1].left=Node(a[i])
            stack.append(stack[-1].left)
    return root
class Node:
    def __init__(self,data):
        self.data=data
        self.left=None
        self.right=None  
a=[40,30,35,80,100]
n=5
root=preordertoposorder(a,n)
postorder(root)
# print(root.data)
# print(root.left.data)
# print(root.right.data)
# print(root.left.right.data)
# print(root.right.right.data)