PYTHON: My program was supposed to identify the orders of the missing traversal, which is either the preorder or postorder. However, my program only works in ide
PYTHON:
My program was supposed to identify the orders of the missing traversal, which is either the preorder or postorder. However, my program only works in identifying the PREORDER. There is something wrong with the function of my POSTORDER. Can you please identify the problem and fix it? I will also add an image below for the expected output and for your reference. Thank you.
# Main program
inorder_list = []
preorder_list = []
postorder_list = []
n = int(input("How many nodes want to enter? "))
# Methods
def searchR(arr, x, n): # CHANGED THE NAME OF FUNCTION AS THERE ARE TWO FUNCTION WITH SAME NAME
for i in range(n):
if (arr[i] == x):
return i
return -1
def PostOrderT(Ino, preo, n):
root = searchR(Ino, preo[0], n)
if (root != 0):
PostOrderT(Ino, preo[1:n], root)
if (root != n - 1):
PostOrderT(Ino[root + 1:n], preo[root + 1:n], n - root - 1)
print(preo[0], end=" ")
# Make new node
class newNode:
def __init__(self, data):
self.data = data
self.left = self.right = None
# Construct binary tree
def MakeTree(Ino, posto, inoStrt, inoEnd, p_Index):
if (inoStrt > inoEnd):
return None
node = newNode(posto[p_Index[0]])
p_Index[0] -= 1
if (inoStrt == inoEnd):
return node
iIndex = search(Ino, inoStrt, inoEnd, node.data)
node.right = MakeTree(Ino, posto, iIndex + 1, inoEnd, p_Index)
node.left = MakeTree(Ino, posto, inoStrt, iIndex - 1, p_Index)
return node
def bTree(Ino, posto, n):
p_Index = [n - 1]
return MakeTree(Ino, posto, 0, n - 1, p_Index)
def search(arr, astrt, aend, value):
i = 0
for i in range(astrt, aend + 1):
if (arr[i] == value):
break
return i
def PreOrderT(node):
if node == None:
return
print(node.data, end=" ")
PreOrderT(node.left)
PreOrderT(node.right)
print("Enter INORDER:")
for i in range(0, n):
ele = input().split()
if len(ele) == n:
for i in ele:
inorder_list.append(i) # adding the element
break
elif len(ele) > n:
print("You have entered more nodes")
break
else:
print("You have entered less nodes")
break
print(inorder_list)
print("\nWould you like to use Preorder or Postorder?")
choice = int(input("Press [1] for PREORDER and Press [2] for POSTORDER>> "))
if choice == 1:
print("Enter PREORDER: ")
for i in range(0, n):
ele = input().split()
if len(ele) == n:
for i in ele:
preorder_list.append(i) # adding the element
break
elif len(ele) > n:
print("You have entered more nodes")
break
else:
print("You have entered less nodes")
break
print(preorder_list)
print("\nMissing Traversal Identified!")
print("POSTORDER traversal: ")
bTree(inorder_list, preorder_list, n) # NEED TO BUILD THE TREE FIRST
PostOrderT(inorder_list, preorder_list, n) # CALLING CORRECT FUNCTION
elif choice == 2:
print("Enter POSTORDER: ")
for i in range(0, n):
ele = input().split()
if len(ele) == n:
for i in ele:
postorder_list.append(i) # adding the element
break
elif len(ele) > n:
print("You have entered more nodes")
break
else:
print("You have entered less nodes")
break
print(postorder_list)
print("\nMissing Traversal Identified!")
print("PREORDER traversal: ")
PostOrderT(inorder_list, preorder_list, n)
else:
print("Invalid choice")
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