Can someone tell me why my code here doesn't work?

Input:

3, 7

Output:

[[1,5],[2,4],[1,2,4]]

Expected:

[[1,2,4]]

```
public class Solution {
static List<List<Integer>> res = new ArrayList<List<Integer>>();
public List<List<Integer>> combinationSum3(int k, int n) {
if (k==0 || n>45) return res;
helper(new ArrayList<Integer>(), 1, k, n);
return res;
}
public static void helper(List<Integer> curr, int start, int k, int n){
if (curr.size()==k){
if (n==0){
res.add(new ArrayList(curr));
}
return;
}
for (int i=start; i<=9; i++){
curr.add(i);
helper(curr, i+1, k, n-i);
curr.remove(curr.size()-1);
}
}
}
```