# Definition for a binary tree node.
# class TreeNode(object):
# def __init__(self, x):
# self.val = x
# self.left = None
# self.right = None
class Codec:
def serialize(self, root):
"""Encodes a tree to a single string.
:type root: TreeNode
:rtype: str
"""
nodes = []
queue = deque()
if root:
queue.append(root)
while queue:
node = queue.popleft()
if node:
nodes.append(node.val)
queue.append(node.left)
queue.append(node.right)
else:
nodes.append(None)
while 1:
if nodes and nodes[-1] is None:
nodes.pop()
else:
break
return json.dumps(nodes)
def deserialize(self, data):
"""Decodes your encoded data to tree.
:type data: str
:rtype: TreeNode
"""
nodes = json.loads(data)
n = len(nodes)
if n == 0:
return None
queue = deque()
root = TreeNode(nodes[0])
queue.append(root)
i = 1
while queue:
if i >= n:
break
num_cur_layer = len(queue)
for _ in range(num_cur_layer):
node = queue.popleft()
if i >= n or nodes[i] is None:
node.left = None
else:
new_node = TreeNode(nodes[i])
node.left = new_node
queue.append(new_node)
i += 1
if i >= n or nodes[i] is None:
node.right = None
else:
new_node = TreeNode(nodes[i])
node.right = new_node
queue.append(new_node)
i += 1
return root
# Your Codec object will be instantiated and called as such:
# codec = Codec()
# codec.deserialize(codec.serialize(root))