给定一个二叉树，返回所有从根节点到叶子节点的路径。
说明: 叶子节点是指没有子节点的节点。
示例:
输入:
1
/ \
2 3
\
5
输出: ["1->2->5", "1->3"]
解释: 所有根节点到叶子节点的路径为: 1->2->5, 1->3# Definition for a binary tree node.
# class TreeNode:
# def __init__(self, x):
# self.val = x
# self.left = None
# self.right = None
class Solution:
def binaryTreePaths(self, root):
"""
:type root: TreeNode
:rtype: List[str]
"""
path=''
result=[]
self.echo(root,path,result)
return result
def echo(self,root,path,result):
if not root:
return
path+=str(root.val)
if root.left:
self.echo(root.left,path + '->',result)
if root.right:
self.echo(root.right,path + '->',result)
if not root.left and not root.right:
result.append(path)
