请检查我的代码。我找不到错误在哪里。问题是here。二叉树路径总和(python)
这里是我的解决方案:
# Given a binary tree, find all paths that sum of the nodes in the path equals to a given number target.
#
# A valid path is from root node to any of the leaf nodes.
# Example
# Given a binary tree, and target = 5:
#
# 1
# /\
# 2 4
# /\
# 2 3
# return
#
# [
# [1, 2, 2],
# [1, 4]
# ]
class TreeNode:
def __init__(self, x):
self.val = x
self.left = None
self.right = None
class Solution:
# @param {TreeNode} root the root of binary tree
# @param {int} target an integer
# @return {int[][]} all valid paths
result = []
def binaryTreePathSum(self, root, target):
# Write your code here
if root is None:
return self.result
self.dfs(root, [], target)
return self.result
def dfs(self, node, tmp, target):
tmp.append(node.val)
if node.left is None and node.right is None:
if target == sum(tmp):
#print tmp
self.result.append(tmp)
tmp.pop()
return
if node.left:
self.dfs(node.left, tmp, target)
if node.right:
self.dfs(node.right, tmp, target)
tmp.pop()
if __name__ == "__main__":
root = TreeNode(1)
root.left = TreeNode(2)
root.left.left = TreeNode(2)
root.left.right = TreeNode(3)
root.right = TreeNode(4)
result = Solution().binaryTreePathSum(root, 5)
print result
我们假设输入为{1,2,4,2,3}, 5
。运行该解决方案后,输出为[[],[]]
。但是,如果我取消缩进了print tmp
,输出将是
[1, 2, 2]
[1, 4]
[[],[]]
的tmp
输出是正确的。但似乎result.append(tmp)
没有将tmp
附加到result
。我不知道问题在哪里。
1.我看不到你的“问题”,因为我没有lintcode帐户,我不愿意创建一个。 2.什么是'{1,2,4,2,3}'?这应该是一组?因为如果它是一个集合,它就等于'{1,2,3,4}'。 3. *“假设输入是......”*输入_what_?如果你将这些参数传递给'binaryTreepathSum',它会抛出一个AttributeError。 –
请__填写完整的代码___(不要让人们讨论你要做的事情)。检查[\ [SO \]:MCVE](https://stackoverflow.com/help/mcve)或[\ [SO \]:如何问](https://stackoverflow.com/help/how-to-问)。无论如何,它应该是简单的东西(对于缩进缺乏抱歉,但它不可能在注释中):'def tree_sum(tree):if tree is None:return 0 else:return tree.val + tree_sum(tree.left)+ tree_sum(tree.right)'。 – CristiFati
对不起,我添加了完整的代码和问题描述。 – Bramble