def append(self, value):
newNode = TwoWayNode(value)
if self.size == 0:
self.tail = newNode
self.head = newNode
else:
self.tail.next = newNode
newNode.previous = self.tail
self.tail = self.tail.next
self.size += 1
def append(self, data):
node = TwoWayNode(data)
if self.head == None:
self.head = node
self.head.next = self.head
self.tail = self.head
self.size += 1
else:
probe = self.head
while probe.next != self.head:
probe = probe.next
probe.next = node
node.next = self.head
node.previous = probe
self.tail = node
self.size += 1
def enqueue(self, data):
new_node = TwoWayNode(data)
if self.count == 0:
self.head = new_node
self.head.next = self.head
self.tail = self.head
else:
probe = self.head
while probe.next != self.head:
probe = probe.next
probe.next = new_node
new_node.next = self.head
new_node.previous = probe
self.tail = new_node
self.count += 1
def makeTwoWay(listHead):
'''
This function takes in the "head" of a singly-linked-list, creates a
doubly-linked-list with the same data, and returns the head and tail of the
created list.
@param listHead: the pointer to the first node of a singly-linked-list
'''
probe = listHead
newListHead = TwoWayNode(probe.data) #creates first node and point to it
tempPointer = newListHead #pointer used to move forward while creating
newListTail = None #to point at the end of the list later
while probe.next != None and probe.next != listHead:
probe = probe.next
tempPointer.next = TwoWayNode(probe.data, tempPointer, None)
tempPointer = tempPointer.next
newListTail = tempPointer #assigns tail pointer to last node
tempPointer.next = newListHead #points the "next" pointer of last node to first node
newListHead.previous = newListTail #points the "previous" pointer of first node to last node
print("Circular Doubly linked list created.")
return (newListHead, newListTail)