LeetCode-Path Sum II

/**
 * Definition for binary tree
 * struct TreeNode {
 *     int val;
 *     TreeNode *left;
 *     TreeNode *right;
 *     TreeNode(int x) : val(x), left(NULL), right(NULL) {}
 * };
 */
class Solution {
public:
    vector<vector<int> > pathSum(TreeNode *root, int sum) {
        // Start typing your C/C++ solution below
        // DO NOT write int main() function
        vector<vector<int> > paths;
        vector<int> curPath;
        dfs(root, sum, paths, curPath);
        return paths;
    }
    
    void dfs(TreeNode *root, int curRest, vector<vector<int> > &paths, vector<int> &curPath)
    {
        if (root == NULL)
            return;
        curPath.push_back(root->val);
        if (root->left == NULL && root->right == NULL)
        {
            if (root->val == curRest)
                paths.push_back(curPath);
        }    
        else
        {
            dfs(root->left, curRest - root->val, paths, curPath);
            dfs(root->right, curRest - root->val, paths, curPath);
        }
        curPath.pop_back();
    }
};