class Queue(Generic[T]):
llist = LinkedList.DoublyLinkedList()
def __init__(self, first_elem=None):
if first_elem is not None:
self.offer(first_elem)
# return the size of the queue
def size(self):
return self.llist.size
def isEmpty(self):
return self.size() == 0
# peek the element at the front of the queue
# the method throws an error if the queue is empty
def peek(self):
if self.isEmpty():
raise QueueError("Queue is empty!")
return self.llist.peekFirst()
# poll an element from the front of the queue
# the method throws an error if the queue is empty
def poll(self):
if self.isEmpty():
raise QueueError("Queue is empty!")
return self.llist.removeLast()
# add an element to the back of the queue
def offer(self, elem):
self.llist.addLast(elem)
def main():
data1 = "hello"
data2 = "I"
data3 = "am"
data4 = "your"
data5 = "father"
data6 = "luke"
data7 = "skywalker"
linked_list = LinkedList.DoublyLinkedList()
linked_list.add(data1)
linked_list.add(data2)
linked_list.add(data3)
linked_list.add(data4)
linked_list.add(data5)
linked_list.add(data6)
linked_list.add(data7)
print(linked_list)
linked_list.removeFirst()
linked_list.removeLast()
print(linked_list)
print(linked_list.contains("your"))
print(linked_list.peekLast())
def __init__(self, firstElem):
self.linked_list = LinkedList.DoublyLinkedList()
if firstElem is not None:
self.push(firstElem)
