【leetcode❤python】 257. Binary Tree Paths

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# Definition for a binary tree node.
# class TreeNode:
#     def __init__(self, x):
#         self.val = x
#         self.left = None
#         self.right = None

class Solution:
    # @param {TreeNode} root
    # @return {string[]}
    
    resultList=[]
    def binaryTreePaths(self, root):
        self.resultList=[]
        if root==None:
            return []
        else:
            self.resultList.append(str(root.val))
            self.dfs(root)
       
        return self.resultList
        
    def dfs(self,root):
      
        curVal=self.resultList[-1]
       
        if root.left!=None or root.right!=None:
            self.resultList.pop()
        else:return
         
        if root.left!=None:
            val=str(curVal)+'->'+str(root.left.val)
            self.resultList.append(val)
            self.dfs(root.left)
        if root.right!=None:
            val=str(curVal)+'->'+str(root.right.val)
            self.resultList.append(val)
            self.dfs(root.right)