LinearDataStructures/queue.py at master · brianramaswami/LinearDataStructures · GitHub

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from node import Node

class Queue:
  def __init__(self, max_size=None):
    self.head = None
    self.tail = None
    self.max_size = max_size
    self.size = 0

  def enqueue(self, value):
    if self.has_space():
      item_to_add = Node(value)
      print("Adding " + str(item_to_add.get_value()) + " to the queue!")
      if self.is_empty():
        self.head = item_to_add
        self.tail = item_to_add
      else:
        self.tail.set_next_node(item_to_add)
        self.tail = item_to_add
      self.size += 1
    else:
      print("Sorry, no more room!")

  def dequeue(self):
    if self.get_size() > 0:
      item_to_remove = self.head
      print(str(item_to_remove.get_value()) + " is served!")
      if self.get_size() == 1:
        self.head = None
        self.tail = None
      else:
        self.head = self.head.get_next_node()
      self.size -= 1
      return item_to_remove.get_value()
    else:
      print("The queue is totally empty!")

  def peek(self):
    if self.size > 0:
      return self.head.get_value()
    else:
      print("No orders waiting!")

  def get_size(self):
    return self.size

  def has_space(self):
    if self.max_size == None:
      return True
    else:
      return self.max_size > self.get_size()

  def is_empty(self):
    return self.size == 0


print("Creating a deli line with up to 10 orders...\n------------")
deli_line = Queue(10)
print("Adding orders to our deli line...\n------------")
deli_line.enqueue("egg and cheese on a roll")
deli_line.enqueue("bacon, egg, and cheese on a roll")
deli_line.enqueue("toasted sesame bagel with butter and jelly")
deli_line.enqueue("toasted roll with butter")
deli_line.enqueue("bacon, egg, and cheese on a plain bagel")
deli_line.enqueue("two fried eggs with home fries and ketchup")
deli_line.enqueue("egg and cheese on a roll with jalapeos")
deli_line.enqueue("plain bagel with plain cream cheese")
deli_line.enqueue("blueberry muffin toasted with butter")
deli_line.enqueue("bacon, egg, and cheese on a roll")
# ------------------------ #
# Uncomment the line below:
deli_line.enqueue("western omelet with home fries")
# ------------------------ #
print("------------\nOur first order will be " + deli_line.peek())
print("------------\nNow serving...\n------------")
deli_line.dequeue()
deli_line.dequeue()
deli_line.dequeue()
deli_line.dequeue()
deli_line.dequeue()
deli_line.dequeue()
deli_line.dequeue()
deli_line.dequeue()
deli_line.dequeue()
deli_line.dequeue()
# ------------------------ #
# Uncomment the line below:
deli_line.dequeue()
# ------------------------ #