def merge(left, right):
"""
Merges 2 link list, sorting data in nodes
return a new merged list
"""
# create a new linked list that contains nodes from left, right
merged = LinkedList()
# Add a fake head that is discarded later
merged.add(0)
# Set current to the head of linked list
current = merged.head
# Obtain head nodes for left and right lists
left_head = left.head
right_head = right.head
# Iterate over left and right until we reach the tail node of either
while left_head or right_head:
# if the head node of left is none are past the tail
# add the node from right to merged linked list
if left_head is None:
current.next_node = right_head
# call next on right to set loop condition to false
right_head = right_head.next_node
# if the head node of right is None we are past the tail
# add the tail node from left to merged linked list
elif right_head is None:
current.next_node = left_head
# call next on left to set loop condition to false
left_head = left_head.next_node
else:
# Not at either tail node
# obtain node data o perform comparison operations
left_data = left_head.data
right_data = right_head.data
# if data on left is less than right, set current to left node
if left_data < right_data:
current.next_node = left_head
# move left head to next node
left_head = left_head.next_node
# if data on left is greater than right, set current to right node
else:
current.next_node = right_head
# move right head to next node
right_head = right_head.next_node
# move current to next node
current = current.next_node
# discard fake head and set first merged node as head
head = merged.head.next_node
merged.head = head
return merged
def split(ll):
if ll is None or ll.head is None:
left_half = ll
right_half = None
return left_half, right_half
else:
size = ll.size()
mid = size // 2
mid_node = ll.node_at_index(mid - 1)
left_half = ll
right_half = LinkedList()
right_half.head = mid_node.next_node
mid_node.next_node = None
return left_half, right_half