leetcode-面试题34- 二叉树中和为某一值的路径

题目描述：

 

 提交：

class Solution:
    def pathSum(self, root: TreeNode, sum: int) -> List[List[int]]:
        def helper(num,node,temp):
            if node.left:
                helper(num+node.left.val,node.left,temp+[node.left.val])
            if node.right:
                helper(num+node.right.val,node.right,temp+[node.right.val])
            if not node.right and not node.left:
                if num == sum:
                    res.append(temp)
                return
        
        res = []
        if not root:
            return []
        helper(root.val,root,[root.val])

        return res