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Copy path05_doublyLL_remove_duplicates.py
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05_doublyLL_remove_duplicates.py
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class Node:
def __init__(self, data):
self.data = data
self.next = None
self.prev = None
class DoublyLinkedList:
def __init__(self):
self.head = None
def append(self, data):
new_node = Node(data)
if self.head is None:
new_node.prev = None
self.head = new_node
else:
cur = self.head
while cur.next:
cur = cur.next
cur.next = new_node
new_node.prev = cur
new_node.next = None
def prepend(self, data):
new_node = Node(data)
if self.head is None:
new_node.prev = None
self.head = new_node
else:
self.head.prev = new_node
new_node.next = self.head
self.head = new_node
new_node.prev = None
def delete_node(self, node):
cur = self.head
while cur:
if cur == node and cur == self.head:
# Case 1:
if not cur.next:
cur = None
self.head = None
return
# Case 2:
else:
nxt = cur.next
cur.next = None
cur = None
nxt.prev = None
self.head = nxt
return
elif cur == node:
# Case 3:
if cur.next:
nxt = cur.next
prev = cur.prev
prev.next = nxt
nxt.prev = prev
cur.next = None
cur.prev = None
cur = None
return
# Case 4:
else:
prev = cur.prev
prev.next = None
cur.prev = None
cur = None
return
cur = cur.next
def print_list(self):
cur = self.head
while cur:
print(cur.data)
cur = cur.next
def remove_duplicates(self):
cur = self.head
seen = dict()
while cur:
if cur.data not in seen:
seen[cur.data] = 1
cur = cur.next
else:
nxt = cur.next
self.delete_node(cur)
cur = nxt
dllist = DoublyLinkedList()
dllist.append(1)
dllist.append(1)
dllist.append(4)
dllist.append(2)
dllist.append(3)
dllist.append(6)
dllist.append(1)
dllist.append(3)
dllist.append(4)
dllist.append(3)
dllist.append(4)
dllist.append(5)
dllist.append(7)
dllist.append(7)
dllist.append(5)
dllist.append(7)
dllist.print_list()
print("\n")
dllist.remove_duplicates()
dllist.print_list()