Factor Combinations

又成一道新知。

public class Solution {    public List<List<Integer>> getFactors(int n) {        List<List<Integer>> results = new LinkedList<>();        List<Integer> list = new LinkedList<>();        getFactorsHelper(n, results, list, 0);        return results;    }        private void getFactorsHelper(int n, List<List<Integer>> results, List<Integer> list, int last){        for (int i = 2; i < n; i++) {            if (n / i >= i && i >= last && n % i == 0) {                list.add(i);                list.add(n / i);                results.add(new LinkedList<>(list));                list.remove(list.size() - 1);                getFactorsHelper(n / i, results, list, i);                list.remove(list.size() - 1);            }        }    }}