def create_lists_3_helper(r, lists, level):
if not r:
return
# if the level is not visited before, create a new list
if level>len(lists)-1:
current_list=LinkList()
current_list.append_node(r)
lists.append(current_list)
# else, get the list, append the tree node
else:
current_list=lists[level]
current_list.append_node(r)
create_lists_3_helper(r.left, lists, level+1)
create_lists_3_helper(r.right, lists, level+1)
def create_lists_1(r):
q=deque([])
level=deque([])
lists=[]
q.append(r)
level.append(0)
level_list=LinkList()
level_list.append_node(r)
while q:
current_node=q.popleft()
current_level=level.popleft()
if current_node.left:
q.append(current_node.left)
level.append(current_level+1)
if current_node.right:
q.append(current_node.right)
level.append(current_level+1)
if q:
# if this node is at the same level of the previous node, then add this node to the list
if level[0]==current_level:
level_list.append_node(q[0])
# else, then pack the list to lists, create a new list, and add this node to the list
else:
lists.append(level_list)
level_list=LinkList()
level_list.append_node(q[0])
# if it's the last element, pack to lists
else:
lists.append(level_list)
return lists
def create_lists_2(r):
lists=[]
current=LinkList()
if r:
current.append_node(r)
while len(current)>0:
lists.append(current) # pack to lists
parents=current # go one level down
current=LinkList() # create a new list
for parent in parents:
if parent.left:
current.append_node(parent.left)
if parent.right:
current.append_node(parent.right)
return lists
