输出所有和为S的连续正数序列。序列内按照从小至大的顺序，序列间按照开始数字从小到大的顺序

import java.util.*;
public class Solution {
    public ArrayList<ArrayList<Integer> > FindContinuousSequence(int sum) {
        if(sum < 0){
            return null;
        }
        ArrayList<ArrayList<Integer>> list = new ArrayList<ArrayList<Integer>>();


        for(int i = 1; i <= sum/2; i++){
            ArrayList<Integer> subList = new ArrayList<Integer>();
            int res = 0;
            for(int j =  i; j < sum && res<sum ;j++ ){
                res = res + j;
                if(res<sum){
                    subList.add(j);
                }
                if(res == sum){
                    subList.add(j);
                    list.add(subList);
                }
            }
        }
        return list;
    }
}