solution.py

from collections import deque
from typing import List, Optional


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


class Solution:
    def pathSum(self, root: Optional[TreeNode], targetSum: int) -> List[List[int]]:
        if not root:
            return []

        paths = []
        queue = deque([[root, [root.val], targetSum-root.val]])
        while queue:
            node, path, current_sum = queue.popleft()
            left_node, right_node = node.left, node.right
            if not left_node and not right_node and current_sum == 0:
                paths.append(path)
            if left_node:
                queue.append([left_node, path+[left_node.val], current_sum-left_node.val])
            if right_node:
                queue.append([right_node, path+[right_node.val], current_sum-right_node.val])

        return paths