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

vector<vector<int> > result;

vector<int> v;

generatePathSum(root, sum, v, result);

return result;

}

void generatePathSum(TreeNode *root, int sum, vector<int> v, vector<vector<int> >& result) {

if (root==NULL) {

return;

}

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

if (root->val == sum){

v.push_back(root->val);

result.push_back(v);

}

return;

}

v.push_back(root->val);

if (root->left) {

generatePathSum(root->left, sum - root->val, v, result);

}

if (root->right) {

generatePathSum(root->right, sum - root->val, v, result);

}

}