def partition(head, x):
if head == None: return
p1 = head
p2 = head
after = None
while p2 != None:
if p2.get_data() > x:
# copy to after and delete current
if after == None:
after = Node(p2.get_data())
else:
after.append_to_tail(p2.get_data())
# if p2 is head
if p2 == head:
head = head.get_next()
p1 = head
p2 = head
else:
p1.set_next(p2.get_next())
p2 = p2.get_next()
else:
p1 = p2
p2 = p2.get_next()
# append to end
p1.set_next(after)
return head
def test(self):
head = Node(0)
for i in range(1, 10):
head.append_to_tail(i)
head.print_all_data()
self.assertEqual(find_kth_last_element2(3, head), 7)
self.assertEqual(find_kth_last_element2(10, head), 0)
self.assertEqual(find_kth_last_element2(12, head), None)
p1 = head
p2 = head.get_next().get_next()
if p2 == None: return
while p2 != None and p2.get_next() != None:
p2 = p2.get_next().get_next()
p1 = p1.get_next()
p1.set_next(p1.get_next().get_next())
return head
## given only access to that node.
def delete_middle(node):
# copy the next node to current position, then delete next
node.set_data(node.get_next().get_data())
node.set_next(node.get_next().get_next())
# if 'node' is the last one, mark as dummy
#---------------
head = Node(0)
for i in range(1, 9):
head.append_to_tail(i)
head.print_all_data()
print '----------------'
delete_middle(head)
head.print_all_data()
