/**

 * Definition for binary tree

 * struct TreeNode {

 *     int val;

 *     TreeNode *left;

 *     TreeNode *right;

 *     TreeNode(int x) : val(x), left(NULL), right(NULL) {}

 * };

 */

class Solution {

private:

    vector<vector<int> > paths;

public:

    void dfs(TreeNode *node,int sum,int csum,vector<int> onePath){    //a能为引用

        if(node==NULL)

            return;

        if(node->left==NULL && node->right==NULL){

            if(node->val+csum==sum){

                onePath.push_back(node->val);

                paths.push_back(onePath);

            }

            return;

        }

        onePath.push_back(node->val);

        dfs(node->left,sum,csum+node->val,onePath);

        dfs(node->right,sum,csum+node->val,onePath);

    }

    vector<vector<int> > pathSum(TreeNode *root, int sum) {

        paths.clear();

        vector<int> onePath;

        dfs(root,sum,,onePath);

        return paths;

    }

};