Description
Serialization is 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 search tree. There is no restriction on how your serialization/deserialization algorithm should work. You need to ensure that a binary search tree can be serialized to a string, and this string can be deserialized to the original tree structure.
The encoded string should be as compact as possible.
Example 1:
Input: root = [2,1,3] Output: [2,1,3]
Example 2:
Input: root = [] Output: []
Constraints:
- The number of nodes in the tree is in the range
[0, 104]. 0 <= Node.val <= 104- The input tree is guaranteed to be a binary search tree.
Solution
Python3
class Codec:
def serialize(self, root):
vals = []
def preOrder(node):
if node:
vals.append(node.val)
preOrder(node.left)
preOrder(node.right)
preOrder(root)
return ' '.join(map(str, vals))
# O( N ) since each val run build once
def deserialize(self, data):
vals = collections.deque(int(val) for val in data.split())
def build(minVal, maxVal):
if vals and minVal < vals[0] < maxVal:
val = vals.popleft()
node = TreeNode(val)
node.left = build(minVal, val)
node.right = build(val, maxVal)
return node
return build(float('-infinity'), float('infinity'))