Doubly Linked List Python

 

# singly linked list

class Node:

  def __init__(self,data):

    self.data = data

    self.prev = None

    self.next = None

class dl:

  def __init__(self):

    self.head = None

    self.tail = None

 

  def is_empty(self):

    return self.head is None

 

  def insertb(self,value):

    new_node = Node(value)

    if self.is_empty():

      self.head = self.tail = new_node

    else:

      new_node.next = self.head

      self.head.prev = new_node

      self.head = new_node

 

  def inserte(self,value):

    new_node = Node(value)

    if self.is_empty():

      self.head = self.tail = new_node

    else:

      new_node.prev = self.tail

      self.tail.next = new_node

      self.tail = new_node

 

  def forward(self):

    current = self.head

    while current:

      if current.data != None:

        print(current.data,'<->',end='')

      current = current.next

    print()

  def backward(self):

    current = self.tail

    while current:

      if current.data != None:

        print(current.data,'<->',end='')

      current = current.prev

    print()

  def delete(self,value):

    current = self.head

    while current:

      if current.data != None and current.data == value:

        current.data = None

      current = current.next

    print("deleted...")

    self.forward()

    self.backward()

    self.size()

 

  def update(self,value,replace):

    current = self.head

    while current:

      if current.data != None and current.data == value:

        current.data = replace

      current = current.next

    print("updated...")

    self.forward()

    self.backward()

   

  def size(self):

    current = self.head

    size=0

    while current:

      if current.data != None :

        size += 1

      current = current.next

    print(f"size is {size}...!")

 

l = dl()

l.insertb(1)

l.insertb(2)

l.insertb(3)

l.inserte(4)

l.inserte(5)

l.delete(1)

l.update(2,22)

Singly linked list python

 

# singly linked list

class Node:

  def __init__(self,data):

    self.data = data

    self.next = None

class ll:

  def __init__(self):

    self.head = None

 

  def is_empty(self):

    return self.head is None

 

  def insert(self,value):

    new_node = Node(value)

    if self.is_empty():

      self.head = new_node

    else:

      new_node.next = self.head

      self.head = new_node

 

  def show(self):

    current = self.head

    while current:

      if current.data != None:

        print(current.data,'->',end='')

      current = current.next

    print()

 

  def delete(self,value):

    current = self.head

    while current:

      if current.data != None and current.data == value:

        current.data = None

      current = current.next

    print("deleted...")

    self.show()

    self.size()

# if you wish to delete the node and don't want none

    def delete(self,value):

        current = self.head

        while current:

            if current.data == value:

                previous.next = current.next  # Skip over the node to delete it

                current = None  # Optional: free the node

                print(f"Node with value {value} deleted.")

                self.display()

                return

            previous = current

            current = current.next

 

  def update(self,value,replace):

    current = self.head

    while current:

      if current.data != None and current.data == value:

        current.data = replace

      current = current.next

    print("updated...")

    self.show()

   

  def size(self):

    current = self.head

    size=0

    while current:

      if current.data != None :

        size += 1

      current = current.next

    print(f"size is {size}...!")

 

l = ll()

l.insert(1)

l.insert(2)

l.insert(3)

l.insert(4)

l.insert(5)

l.show()

BST python

class Tree:

  def __init__(self,data):

    self.data = data

    self.left = None

    self.right = None

 

  def is_empty(self):

    return self.data is None

 

  def insert(self,value):

    if value < self.data:

      if self.left is None :

        self.left = Tree(value)

      else:

        self.left.insert(value)

   

    if value > self.data :

      if self.right is None:

        self.right = Tree(value)

      else:

        self.right.insert(value)

       

  def show_left(self):

    current = self.left

    while current:

      if current.data != None:

        print(current.data)

      current = current.left

    print()

   

  def show_right(self):

    current = self.right

    while current:

      if current.data != None:

        print(current.data)

      current = current.right

    print()

   

def delete(root):

  value=-3

  if root:

    delete(root.left)

    delete(root.right)

    if root.data == value and root.data != None:

      root.data = None

     

     

def preorder(root):

  if root and root.data != None:

    print(root.data)

    preorder(root.left)

    preorder(root.right)

def postorder(root):

  if root and root.data != None:

    postorder(root.left)

    postorder(root.right)

    print(root.data)

def inorder(root):

  if root and root.data != None:

    inorder(root.left)

    print(root.data)

    inorder(root.right)

   

   

   

   

root = Tree(1)

root.insert(2)

root.insert(3)

root.insert(4)

root.insert(-1)

root.insert(-2)

root.insert(-3)

root.show_left()

root.show_right()

delete(root)

root.show_right()

root.show_left()

preorder(root)

postorder(root)

inorder(root)