Una cola es una colección de objetos que se insertan y eliminan utilizando el principio de primero en entrar, primero en salir (FIFO). La inserción se realiza en la parte posterior (posterior) de la cola y se accede a los elementos y se eliminan desde la primera ubicación (frontal) en la cola.
Operaciones de cola:
1. enqueue() : Adds element to the back of Queue. 2. dequeue() : Removes and returns the first element from the queue. 3. first() : Returns the first element of the queue without removing it. 4. size() : returns the number of elements in the Queue. 5. isEmpty() : Return True if Queue is Empty else return False. 6. printqueue() : Print all elements of the Queue.
A continuación se muestra la implementación de las operaciones de cola mencionadas anteriormente utilizando Doubly LinkedList en Python:
# A complete working Python program to demonstrate all
# Queue operations using doubly linked list
# Node class
class Node:
# Function to initialise the node object
def __init__(self, data):
self.data = data # Assign data
self.next = None # Initialize next as null
self.prev = None # Initialize prev as null
# Queue class contains a Node object
class Queue:
# Function to initialize head
def __init__(self):
self.head = None
self.last=None
# Function to add an element data in the Queue
def enqueue(self, data):
if self.last is None:
self.head =Node(data)
self.last =self.head
else:
self.last.next = Node(data)
self.last.next.prev=self.last
self.last = self.last.next
# Function to remove first element and return the element from the queue
def dequeue(self):
if self.head is None:
return None
else:
temp= self.head.data
self.head = self.head.next
self.head.prev=None
return temp
# Function to return top element in the queue
def first(self):
return self.head.data
# Function to return the size of the queue
def size(self):
temp=self.head
count=0
while temp is not None:
count=count+1
temp=temp.next
return count
# Function to check if the queue is empty or not
def isEmpty(self):
if self.head is None:
return True
else:
return False
# Function to print the stack
def printqueue(self):
print("queue elements are:")
temp=self.head
while temp is not None:
print(temp.data,end="->")
temp=temp.next
# Code execution starts here
if __name__=='__main__':
# Start with the empty queue
queue = Queue()
print("Queue operations using doubly linked list")
# Insert 4 at the end. So queue becomes 4->None
queue.enqueue(4)
# Insert 5 at the end. So queue becomes 4->5None
queue.enqueue(5)
# Insert 6 at the end. So queue becomes 4->5->6->None
queue.enqueue(6)
# Insert 7 at the end. So queue becomes 4->5->6->7->None
queue.enqueue(7)
# Print the queue
queue.printqueue()
# Print the first element
print("\nfirst element is ",queue.first())
# Print the queue size
print("Size of the queue is ",queue.size())
# remove the first element
queue.dequeue()
# remove the first element
queue.dequeue()
# first two elements are removed
# Print the queue
print("After applying dequeue() two times")
queue.printqueue()
# Print True if queue is empty else False
print("\nqueue is empty:",queue.isEmpty())
Producción:
Queue operations using doubly linked list queue elements are: 4->5->6->7-> first element is 4 Size of the queue is 4 After applying dequeue() two times queue elements are: 6->7-> queue is empty: False
Publicación traducida automáticamente
Artículo escrito por ASWIN_SIVAPRAKASH y traducido por Barcelona Geeks. The original can be accessed here. Licence: CCBY-SA