# Definition for a binary tree node.

# class TreeNode:

#     def __init__(self, x):

#         self.val = x

#         self.left = None

#         self.right = None

class Solution:

    def pathSum(self, root: TreeNode, sum: int) -> List[List[int]]:

        res, lst = [], []

        self.helper(root, sum, res, lst)

        return res

    def helper(self, root, sum, res, lst):

        if root is None:

            return

        if root.left is None and root.right is None:

            if sum == root.val:

                lst.append(root.val)

                res.append(list(lst))

                lst.pop()

                return

        lst.append(root.val)

        left = self.helper(root.left, sum - root.val, res, lst)

        right = self.helper(root.right, sum - root.val, res, lst)

        lst.pop()