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297.py
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297.py
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__________________________________________________________________________________________________
sample 72 ms submission
# 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
"""
result = []
queue = [root]
while queue:
cur = queue.pop(0)
result.append(str(cur.val) if cur else 'null')
if cur:
queue.append(cur.left)
queue.append(cur.right)
while result and result[-1] == 'null':
result.pop()
return '[' + ','.join(result) + ']'
def deserialize(self, data):
"""Decodes your encoded data to tree.
:type data: str
:rtype: TreeNode
"""
def walk(n, i):
if i >= n or data[i] == 'null' or data[i] == '':
return None
node = TreeNode(data[i] if data[i] != '' else '')
node.left = walk(n, 2*i + 1)
node.right = walk(n, 2*i + 2)
return node
data = data[1:-1].split()
return walk(len(data), 0)
# Your Codec object will be instantiated and called as such:
# codec = Codec()
# codec.deserialize(codec.serialize(root))
__________________________________________________________________________________________________
sample 17724 kb submission
class Codec:
def serialize(self, root):
if not root:
return ''
q = [root]
index = 0
while index < len(q):
if q[index]:
q.append(q[index].left)
q.append(q[index].right)
index += 1
while not q[-1]:
q.pop()
return ','.join([str(item.val) if item else '#' for item in q])
def deserialize(self, data):
if not data:
return None
vals = data.split(',') # string list
n = len(data)
index = 0
root = TreeNode(int(vals[0]))
q = [root]
isLeftChild = True
for val in vals[1:]:
if val != '#':
node = TreeNode(int(val))
if isLeftChild:
q[index].left = node
else:
q[index].right = node
q.append(node)
if not isLeftChild:
index += 1
isLeftChild = not isLeftChild
return root
__________________________________________________________________________________________________