Lecture Notes on 01 Apr 2022

class Node (object):
  def __init__ (self, data):
    self.data = data
    self.lc = None
    self.rc = None
    # self.parent = None
    # self.visited = False

class Tree (object):
  def __init__ (self):
    self.root = None
    # self.num_nodes = 0

  # insert data into the tree
  def insert_node (self, data):
    new_node = Node (data)

    if (self.root == None):
      self.root = new_node
      return

    current = self.root
    parent = self.root
    while (current != None):
      parent = current
      if (data < current.data):
        current = current.lc
      else:
        current = current.rc

    if (data < parent.data)
      parent.lc = new_node
    else:
      parent.rc = new_node

  # search for a node with given data
  def search_node (self, data):
    current = self.root
    while (current != None) and (current.data != data):
      if (data < current.data):
        current = current.lc
      else:
        current = current.rc

    return current

  # iorder traversal - left, center, right
  def in_order (self, aNode):
    if (aNode != None):
      self.in_order (aNode.lc)
      print (aNode.data)
      self.in_order (aNode.rc)

  # preorder traversal - center, left, right
  def pre_order (self, aNode):
    if (aNode != None):
      print (aNode.data)
      self.pre_order (aNode.lc)
      self.pre_order (aNode.rc)

  # postorder traversal - left, right, center
  def post_order (self, aNode):
    if (aNode != None):
      self.post_order (aNode.lc)
      self.post_order (aNode.rc)
      print (aNode.data)

  # find the node with the smallest value
  def min_node (self):
    current = self.root
    parent = self.root
    while (current != None):
      parent = current
      current = current.lc
    return parent

  # find the node with the largest value
  def max_node (self):
    current = self.root
    parent = self.root
    while (current != None):
      parent = current
      current = current.rc
    return parent