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CircularDoubleLinkedList.py
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107 lines (91 loc) · 2.84 KB
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class Node(object):
def __init__(self, value=None):
self.value = value
self.next = None
self.prev = None
class CircularDoubleLinkedList(object):
def __init__(self, maxsize=None):
self.maxsize = maxsize
node = Node()
node.next, node.prev = node, node
self.root = node
self.length = 0
def __len__(self):
return self.length
def headnode(self):
return self.root.next
def tailnode(self):
return self.root.prev
def append(self, value):
if self.maxsize is not None and self.length >= self.maxsize:
raise Exception('full')
node = Node(value)
tailnode = self.root.prev or self.root
node.prev = tailnode
node.next = self.root
tailnode.next = node
self.root.prev = node
self.length += 1
def appendleft(self, value):
if self.maxsize is not None and self.length >= self.maxsize:
raise Exception('full')
node = Node(value)
if self.root.next is self.root:
self.root.next = node
node.next = self.root
self.root.prev = node
node.prev = self.root
else:
headnode = self.root.next
node.next = headnode
node.prev = self.root
headnode.prev = node
self.root.next = node
self.length += 1
def remove(self, node):
if node is self.root:
return
else:
node.prev.next = node.next
node.next.prev = node.prev
self.length -= 1
return node
def iter_node(self):
if self.root.next == self.root:
return
curnode = self.root.next
while curnode.next is not self.root:
yield curnode
curnode = curnode.next
yield curnode
def __iter__(self):
for node in self.iter_node():
yield node.value
def iter_node_reverse(self):
if self.root.prev == self.root:
return
else:
curnode = self.root.prev
while curnode.prev is not self.root:
yield curnode
curnode = curnode.prev
yield curnode
def test():
dll = CircularDoubleLinkedList()
assert len(dll) == 0
for i in range(5):
dll.append(i)
assert len(dll) == 5
assert list(dll) == [0, 1, 2, 3, 4]
assert [node.value for node in dll.iter_node()] == [0, 1, 2, 3, 4]
assert [node.value for node in dll.iter_node_reverse()] == [4, 3, 2, 1, 0]
assert dll.headnode().value == 0
dll.remove(dll.headnode())
assert len(dll) == 4
assert dll.headnode().value == 1
assert [i for i in dll] == [1, 2, 3, 4]
dll.appendleft(0)
assert [i for i in dll] == [0, 1, 2, 3, 4]
print('success')
if __name__ == '__main__':
test()