297-serialize-and-deserialize-binary-tree¶
Try it on leetcode
Description¶
Serialization is the process of converting a data structure or object into a sequence of bits so that it can be stored in a file or memory buffer, or transmitted across a network connection link to be reconstructed later in the same or another computer environment.
Design an algorithm to serialize and deserialize a binary tree. There is no restriction on how your serialization/deserialization algorithm should work. You just need to ensure that a binary tree can be serialized to a string and this string can be deserialized to the original tree structure.
Clarification: The input/output format is the same as how LeetCode serializes a binary tree. You do not necessarily need to follow this format, so please be creative and come up with different approaches yourself.
Example 1:

Input: root = [1,2,3,null,null,4,5] Output: [1,2,3,null,null,4,5]
Example 2:
Input: root = [] Output: []
Constraints:
- The number of nodes in the tree is in the range
[0, 104]
. -1000 <= Node.val <= 1000
Solution(Python)¶
# 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 __init__(self):
self.i = 0
def serialize(self, root):
"""Encodes a tree to a single string.
:type root: TreeNode
:rtype: str
"""
if root is None:
return "#"
left = self.serialize(root.left)
right = self.serialize(root.right)
return str(root.val) + "," + left + "," + right
def deserialize(self, data):
"""Decodes your encoded data to tree.
:type data: str
:rtype: TreeNode
"""
def recur():
val = next(vals)
if val == "#":
return None
node = TreeNode(int(val))
node.left = recur()
node.right = recur()
return node
vals = iter(data.split(","))
return recur()
# Your Codec object will be instantiated and called as such:
# ser = Codec()
# deser = Codec()
# ans = deser.deserialize(ser.serialize(root))