def deserialize(data):
"""Decodes your encoded data to tree.
:type data: str
:rtype: TreeNode
"""
if not data or data[0] != "[" or data[-1] != "]":
return None
if len(data) == 2:
return None
s = data[1:-1].split(',')
# print(s)
root, level, level_nodes = None, 0, []
res = []
for val in s:
# every val means a node or None
node = None
if val == "null":
node = None
else:
try:
node = TreeNode(int(val))
node.write = 0
except:
pass
# print(node)
if level == 0:
# root
root = node
level += 1
level_nodes = []
res.append([root])
else:
# append node to last level parents
last_level_nodes = res[level - 1]
saved = False
for item in last_level_nodes:
if item is None:
continue
if item.write == 0:
item.left = node
item.write = 1
saved = True
break
if item.write == 1:
item.right = node
item.write = 2
saved = True
break
if saved:
level_nodes.append(node)
is_full = False
for i in range(len(last_level_nodes) - 1, -1, -1):
if last_level_nodes[i] is None:
continue
if last_level_nodes[i].write == 2:
is_full = True
break
if is_full:
# enter next level
res.append(level_nodes)
level += 1
level_nodes = []
return root
