QueueLinkedList.py

#   Created by Elshad Karimov on 30/05/2020.
#   Copyright © 2020 AppMillers. All rights reserved.


class Node:
    def __init__(self, value=None):
        self.value = value
        self.next = None
    
    def __str__(self):
        return str(self.value)

class LinkedList:
    def __init__(self):
        self.head = None
        self.tail = None
    
    

class Queue:
    def __init__(self):
        self.linkedList = LinkedList()
    
    def __str__(self):
        values = [str(x) for x in self.linkedList]
        return ' '.join(values)
    
    def enqueue(self, value):
        newNode = Node(value)
        if self.linkedList.head == None:
            self.linkedList.head = newNode
            self.linkedList.tail = newNode
        else:
            self.linkedList.tail.next = newNode
            self.linkedList.tail = newNode
    
    def isEmpty(self):
        if self.linkedList.head == None:
            return True
        else:
            return False
    
    def dequeue(self):
        if self.isEmpty():
            return "There is not any node in the Queue"
        else:
            tempNode = self.linkedList.head
            if self.linkedList.head == self.linkedList.tail:
                self.linkedList.head = None
                self.linkedList.tail = None
            else:
                self.linkedList.head = self.linkedList.head.next
            return tempNode
    
    def peek(self):
        if self.isEmpty():
            return "There is not any node in the Queue"
        else:
            return self.linkedList.head
    
    def delete(self):
        self.linkedList.head = None
        self.linkedList.tail = None




# custQueue = Queue()
# custQueue.enqueue(1)
# custQueue.enqueue(2)
# custQueue.enqueue(3)
# print(custQueue)
# print(custQueue.peek())
# print(custQueue)