一个算法题，是在想不出有什么好办法，求教

[zhengwei060024]

问题的原题是从1-10 10个数，要打印其 和为15的所有组合。这个题目非常简单，但是程序要求的是填充指定代码段实现，我想了半天都没法填充指定代码段实现，最后时间不够了，有人可以看看嘛？下面是我的实现，用了一个辅助函数，和题目要求不符。

public class practiceString {
    public  static void main(String [] arg ) {
        getPrintNum(10,15);
    }
    static void get_helpListNum(LinkedList<Integer> temp,int sum) {

        if(temp.size() == 1 || sum == 0) {
            if(sum == 0) {
                System.out.println(_helplist.toString());
                return;
            }
            if(sum == temp.get(0)){
                _helplist.add(sum);
                System.out.println(_helplist.toString());
                _helplist.remove(_helplist.size() -1);
            }

        } else {
            int nRemove = temp.size() - 1;
            LinkedList<Integer> temp2 = new LinkedList<Integer>();
            temp2.addAll(temp);
            LinkedList<Integer>temp3 = new LinkedList<Integer>();


            int nRemoveNum = temp2.remove(nRemove);
            temp3.addAll(temp2);
            if(sum - nRemoveNum < 0) {
                get_helpListNum(temp3,sum);
            } else {
                _helplist.add(nRemoveNum);
                get_helpListNum(temp2,sum - nRemoveNum);
                _helplist.remove(_helplist.size() - 1);
                get_helpListNum(temp3,sum);
            }
        }
    }

    static void getPrintNum( int n, int sum) {
        LinkedList<Integer> temp = new LinkedList<Integer>();
        for(int i = 1; i < n + 1; ++i) {
            temp.add(i);
        }
        get_helpListNum(temp,sum);
    }

    public static LinkedList<Integer> _helplist;

    static {
        _helplist = new LinkedList();
    }
}

题目的要求应该是填充getPrintNum( int n, int sum)这个函数，不能额外添加辅助函数

[qq_32270433]

static void getPrintNum(int n, int sum) {
		Stack<Integer> stack = new Stack<Integer>();
		for (int i = 1; i <= n / 2; i++) {
			int tempSum = sum;
			stack.push(i);
			tempSum = sum - i;
			int popNum = i;
			while (!stack.isEmpty()) {
				popNum++;
				if (tempSum > popNum * 2) {
					stack.push(popNum);
					tempSum -= popNum;
				} else if (tempSum == popNum) {
					stack.push(popNum);
					System.out.println(stack.toString());
					stack.pop();
					popNum = stack.pop();
					tempSum += popNum;
				} else if (tempSum < popNum || popNum == 10) {
					popNum = stack.pop();
					tempSum += popNum;
				}
			}
		}
	}