def even_odd_merge(L: LinkedList):
curr = L.head
final_ll = LinkedList()
# if empty linked list return None
if not curr:
return None
else:
# if not empty linked list
even_head = even_tail = Node(None)
odd_head = odd_tail = Node(None)
count = 0
while curr:
if count == 0:
even_tail.next = curr
even_tail = even_tail.next
elif count == 1:
odd_tail.next = curr
odd_tail = odd_tail.next
curr = curr.next
# alternate between 0 and 1 (bitwise operation)
count ^= 1
# make sure odd_tail which is at end of final_ll is None
# attach odd to even by connecting odd head to even tail
# set final linkedlist to even head
odd_tail.next = None
even_tail.next = odd_head.next
final_ll.head = even_head.next
return final_ll
def list_pivoting(l:LinkedList,x:int):
# 3 nodes with head and iteration pointers(tail)
# 1 for less, equal, and greater
less_head = less_iter = Node(None)
equal_head = equal_iter = Node(None)
greater_head = greater_iter = Node(None)
# empty linkedlist
new_ll=LinkedList()
# pointer to input list head
curr = l.head
# Populates the three lists
# based on comparisons to input list
# add node to node lists and traverse iteration pointers to corresponding next
while curr:
if curr.data < x:
less_iter.next = curr
less_iter = less_iter.next
elif curr.data == x:
equal_iter.next = curr
equal_iter = equal_iter.next
else: # curr.data > x.
greater_iter.next = curr
greater_iter = greater_iter.next
curr = curr.next
# Combines the three lists.
# attach greater to equal and attach equal to less, return
greater_iter.next = None
equal_iter.next = greater_head.next
less_iter.next = equal_head.next
new_ll.head = less_head.next
return new_ll
node2 = Node(2)
node3 = Node(3)
node4 = Node(4)
node5 = Node(5)
node6 = Node(6)
node7 = Node(7)
node8 = Node(8)
node0.next = node1
node1.next = node2
node2.next = node3
node3.next = node4
node4.next = node5
node5.next = node6
node6.next = node7
node7.next = node8
node8.next = node3
l1.head = node0
print(has_cycle(l1))
print("\n")
print(cycle_start(l1))
print("\n")
print(cycle_length(l1))
# cycle start and cycle length both have slow and fast at index 1 and 2 not 0 and 1