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# class TreeNode:#     def __init__(self, x):#         self.val = x#         self.left = None#         self.right = None## # @param root TreeNode类 # @param sum int整型 # @return int整型二维数组## class TreeNode:#     def __init__(self, x):#         self.val = x#         self.left = None#         self.right = None## # @param root TreeNode类 # @param sum int整型 # @return int整型二维数组#class Solution:    def pathSum(self , root , target):        # write code here        def dfs(root, sub_res):            if root is None:                return            if root.left is None and root.right is None:                sub_res.append(root.val)                if sum(sub_res) == target:                    res.append(sub_res[:])                return            else:                sub_res.append(root.val)                if root.left:                    dfs(root.left, sub_res)                    sub_res.pop()                if root.right:                    dfs(root.right, sub_res)                    sub_res.pop()                        res = []        if root is None:            return res                if root.left is None and root.right is None and root.val == target:            res.append([root.val])            return res        dfs(root, [])        return res