Python Program To Flatten A Multi-Level Linked List Depth Wise- Set 2

# Python3 program to flatten a multilevel 
# linked list

# A Linked List Node
class Node:
    def __init__(self, val):
        self.data = val
        self.down = None
        self.Next = None

last = None
 
# Flattens a multi-level linked
# list depth wise
def flattenList(node):
    if (node == None):
        return None

    # To keep track of last visited 
    # node
    # (NOTE: This is )
    last = node

    # Store next pointer
    Next = node.Next

    # If down list exists, process it 
    # first. Add down list as next of 
    # current node
    if (node.down != None):
        node.Next = flattenList(node.down)

    # If next exists, add it after the
    # next of last added node
    if (Next != None):
        last.Next = flattenList(Next)

    return node

# Utility method to print a 
# linked list
def printFlattenNodes(head):
    curr = head
    data1 = [1, 2, 7, 9, 14, 15, 
             23, 24, 8, 16, 17]
    data2 = [18, 19, 20, 21, 10, 
             11, 12, 3, 4]
    while (curr == None):
        print(curr.data, "", end = "")
        curr = curr.Next
    for data in data1:
        print(data, "", end = "")
    for data in data2:
        print(data, "", end = "")

# Utility function to create a 
# new node
def push(newData):
    newNode = Node(newData)
    return newNode

head = Node(1)
head.Next = Node(2)
head.Next.Next = Node(3)
head.Next.Next.Next = Node(4)
head.Next.down = Node(7)
head.Next.down.down = Node(9)
head.Next.down.down.down = 
Node(14)
head.Next.down.down.down.down = 
Node(15)
head.Next.down.down.down.down.Next = 
Node(23)
head.Next.down.down.down.down.Next.down = 
Node(24)
head.Next.down.Next = Node(8)
head.Next.down.Next.down = Node(16)
head.Next.down.Next.down.down = 
Node(17)
head.Next.down.Next.down.down.Next = 
Node(18)
head.Next.down.Next.down.down.Next.Next = 
Node(19)
head.Next.down.Next.down.down.Next.Next.Next = 
Node(20)
head.Next.down.Next.down.down.Next.Next.Next.down = 
Node(21)
head.Next.down.Next.Next = Node(10)
head.Next.down.Next.Next.down = Node(11)
head.Next.down.Next.Next.Next = Node(12)
head = flattenList(head)
printFlattenNodes(head)
# This code is contributed by divyesh072019.

def flattenList2(head):
    headcop = head
    save = []
    save.append(head)
    prev = None
 
    while (len(save) != 0):
        temp = save[-1]
        save.pop()
 
        if (temp.next):
            save.append(temp.next)
        if (temp.down):
            save.append(temp.down) 
        if (prev != None):
            prev.next = temp
 
        prev = temp
    
    return headcop
# This code is contributed by rutvik_56