關於Valid Anagram這一題，補充一個方法，效能109ms：

from collections import Counter

class Solution(object):
    def isAnagram(self, s, t):
        """
        :type s: str
        :type t: str
        :rtype: bool
        """

        s_counter = Counter(s)
        t_counter = Counter(t)

        return s_counter == t_counter
 

題目：
Given a binary tree, return all root-to-leaf paths.

For example, given the following binary tree:

   1
 /   \
2     3
 \
  5

All root-to-leaf paths are:

["1->2->5", "1->3"]

題意：
找出二叉樹的所有路徑。

方法一：效能55ms

# 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 binaryTreePaths(self, root):
        """
        :type root: TreeNode
        :rtype: List[str]
        """
        self.ans = []
        if root == None:
            return self.ans
        def
 
 dfs(root, path):
            if root and root.left is None and root.right is None:
                self.ans.append(path)
            elif root.left:
                root.left = dfs(root.left, path + '->' + str(root.left.val))
            elif root.right:
                root.right = dfs(root.right, path + '->' + str(root.right.val))
            dfs(root, root.val)
            return self.ans