def reorder_list(orig_list):
dummy = ListNode(0)
dummy.next = orig_list.head
p = q = dummy
# find the break point
while p and p.next:
p = p.next.next
q = q.next
# break the list
r = q.next
q.next = None
second_half = LinkList()
second_half.head = r
# reverse the second half
second_half.reverse_list()
# merge
p = orig_list.head
r = second_half.head
while r:
p_next = p.next
r_next = r.next
r.next = p.next
p.next = r
r = r_next
p = p_next
del second_half
return orig_list
def reorder_list(orig_list):
dummy = ListNode(0)
dummy.next = orig_list.head
p = q = dummy
# find the break point
while p and p.next:
p = p.next.next
q = q.next
# break the list
r = q.next
q.next = None
second_half = LinkList()
second_half.head = r
# reverse the second half
second_half.reverse_list()
# merge
p = orig_list.head
r = second_half.head
while r:
p_next = p.next
r_next = r.next
r.next = p.next
p.next = r
r = r_next
p = p_next
del second_half
return orig_list
def merge_two_lists_2(list_1, list_2):
result = LinkList()
result.head = merge_two_lists_helper(list_1.head, list_2.head)
return result
def merge_sort_list(orig_list):
nh = merge_sort_list_helper(orig_list.head)
result_list = LinkList()
result_list.head = nh
return result_list
def merge_sort_list(orig_list):
nh = merge_sort_list_helper(orig_list.head)
result_list = LinkList()
result_list.head = nh
return result_list
def merge_two_lists_2(list_1, list_2):
result = LinkList()
result.head = merge_two_lists_helper(list_1.head, list_2.head)
return result
