binary_tree_paths.py

# -*- coding: utf-8 -*-

class Solution:
 # @param {TreeNode} root the root of the binary tree
 # @return {List[str]} all root-to-leaf paths
 def binaryTreePaths(self, root):
 # Write your code here
 self.ret = []
 self._binaryTreePaths(root, '')
 return self.ret

 def _binaryTreePaths(self, root, path):
 if root:
 path += str(root.val) if not path else ('->' + str(root.val))
 # print path
 if root.left:
 self._binaryTreePaths(root.left, path)
 if root.right:
 self._binaryTreePaths(root.right, path)
 if not (root.left or root.right):
 self.ret.append(path)