LeetCode-257. Binary Tree Paths

https://leetcode.com/problems/binary-tree-paths/

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"]

# 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[]}
    def binaryTreePaths(self, root):
        if not root:
            return []
        if not root.left and not root.right:
            return [str(root.val)]
        left_paths = self.binaryTreePaths(root.left)
        right_paths = self.binaryTreePaths(root.right)
        all_paths = left_paths + right_paths
        return ["%s->%s" % (root.val, path) for path in all_paths]