Leetcode-257题:Binary Tree Paths

题目

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"]

代码

# 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 visit(self, root, cur_path, pathes):
        cur_path.append(root.val)
        if root.left==None and root.right==None:
            pathes.append('->'.join([str(n) for n in cur_path]))
        else:
            if root.left != None:
                self.visit(root.left, cur_path, pathes)
            if root.right != None:
                self.visit(root.right, cur_path, pathes)
        cur_path.pop()

    def binaryTreePaths(self, root):
        """
        :type root: TreeNode
        :rtype: List[str]
        """
        if root == None:
            return []
        res = []
        self.visit(root,[],res)
        return res