def copy_postings_list(L):
if not L:
return None
# Stage 1: Makes a copy of the original list without assigning the jump
# field, and creates the mapping for each node in the original
# list to the copied list.
it = L
while it:
new_node = PostingListNode(it.order, it.next, None)
it.next = new_node
it = new_node.next
# Stage 2: Assigns the jump field in the copied list.
it = L
while it:
if it.jump:
it.next.jump = it.jump.next
it = it.next.next
# Stage 3: Reverts the original list, and assigns the next field of
# the copied list.
it = L
new_list_head = it.next
while it.next:
it.next, it = it.next.next, it.next
return new_list_head
def copy_postings_list(L):
if not L:
return L
it = L
while it:
copy = PostingListNode(it.order, it.next, it.jump)
it.next = copy
it = it.next.next
copy_head = L.next
u = L
while u:
if u.jump:
u.next.jump = u.jump.next
u = u.next.next
# it = L
# while it:
# copy = it.next
# if copy.jump:
# copy.jump = it.jump.next
# it = it.next.next
it = L
while it:
it.next = it.next.next
it = it.next
return copy_head
def create_posting_list(serialized):
key_mapping = dict()
head = None
for (order, _) in reversed(serialized):
head = PostingListNode(order, head)
key_mapping[order] = head
list_it = head
for (_, jump_index) in serialized:
if jump_index != -1:
list_it.jump = key_mapping.get(jump_index, None)
if not list_it.jump:
raise RuntimeError('Jump index out of range')
return head