打卡群刷题总结0602——二叉树的所有路径

# Definition for a binary tree node.
# class TreeNode(object):
#     def __init__(self, val=0, left=None, right=None):
#         self.val = val
#         self.left = left
#         self.right = right
class Solution(object):
    def __init__(self):
        self.res = []

    def helper(self, node, current):
        if node.left:
            tmp = copy.copy(current)
            tmp.append(str(node.left.val))
            self.helper(node.left, tmp)
        if node.right:
            tmp = copy.copy(current)
            tmp.append(str(node.right.val))
            self.helper(node.right, tmp)
        if not node.left and not node.right:
            self.res.append('->'.join(current))

    def binaryTreePaths(self, root):
        """
        :type root: TreeNode
        :rtype: List[str]
        """
        if not root:
            return []

        current = [str(root.val)]
        self.helper(root, current)
        return self.res