You are along the right lines. Try printing out the content of each URL
- one of the pages will match your expression, but has additional
instructions... I think you are reaching the end of their false trail
when you get None returned from the url.
The set of pages themselves are the linked list - each contains a
reference to the next element in the sequence. You don't need one to
solve the problem, the problem *is* the linked list!
An example of a linked list in Python is the following if you are
interested:
class Element (object):
next = None
def __init__(self, content):
self.content = content
class LinkedList (object):
first = None
last = None
def add(self, item):
elmnt = Element(item)
if not self.first:
self.first = elmnt
if self.last:
self.last.next = elmnt
self.last = elmnt
def __iter__(self):
current = self.first
while current:
yield current.content
current = current.next
ll = LinkedList()
for i in range(10):
ll.add(i)
for x in ll:
print "Res: %s" % x
--
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