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107.py
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107.py
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# Definition for a binary tree node.
# class TreeNode(object):
# def __init__(self, x):
# self.val = x
# self.left = None
# self.right = None
class Solution(object):
def levelOrderBottom(self, root):
"""
:type root: TreeNode
:rtype: List[List[int]]
"""
ans = []
if not root:
return ans
que1, que2 = [root], []
while que1 or que2:
if len(que1) > 0:
tmp = []
for p in que1:
tmp.append(p.val)
if p.left:
que2.append(p.left)
if p.right:
que2.append(p.right)
ans.append(tmp[::])
que1 = []
else:
tmp = []
for p in que2:
tmp.append(p.val)
if p.left:
que1.append(p.left)
if p.right:
que1.append(p.right)
ans.append(tmp[::])
que2 = []
return ans[::-1]
# super clean!!!!
def levelOrderBottom(self, root):
if not root:
return []
level = [root]
stack = []
while level:
stack.append([each.val for each in level])
level = [node for each in level for node in (each.left, each.right) if node]
return stack[::-1]