Solution.java

public class Solution {
    public List<List<Integer>> combine(int n, int k) {
        List<List<Integer>> answerList=new ArrayList<List<Integer>>();
        for (int i = 1; i <=n; i++) {
            List<Integer> list=new ArrayList<Integer>();
            list.add(i);
            answerList.add(list);
        }
        for (int i = 0; i <answerList.size(); i++) {
            if (answerList.get(i).size()<k) {
                if ((n-answerList.get(i).get(answerList.get(i).size()-1))<(k-answerList.get(i).size())) {
                    answerList.remove(i);
                    i--;
                }else {
                    for (int j = answerList.get(i).get(answerList.get(i).size()-1)+1; j <=n; j++) {
                        System.out.println("j="+j);
                        List<Integer> alist=new ArrayList<Integer>();
                        for (int l = 0; l <answerList.get(i).size(); l++) {
                            alist.add(answerList.get(i).get(l));
                        }
                        alist.add(j);
                        answerList.add(alist);                        
                    }
                    answerList.remove(i);
                    System.out.println();
                    i--;
                }
            }
        }
        return answerList;
    }
}