解法一:recursion
class Solution {
public:
vector<vector<int>> pathSum(TreeNode* root, int sum) {
vector<vector<int>> res;
vector<int> out;
helper(root, sum, out, res);
return res;
}
void helper(TreeNode* root, int sum, vector<int>& out, vector<vector<int>>& res){
if(!root) return;
out.push_back(root->val);
if(!root->right && !root->left && sum==root->val) res.push_back(out);
helper(root->left, sum-root->val, out, res);
helper(root->right, sum-root->val, out, res);
out.pop_back();
}
};
解法二:non-recursion