常规思路,滑动窗口 ArrayList<ArrayList<Integer>> resList = new ArrayList(); int l = 1, r = 2; while(l<r){ int seq = (l+r)*(r-l+1)/2; if(seq == sum){ ArrayList<Integer> list = new ArrayList(); for(int i = l;i<=r;i++) list.add(i); resList.add(list); l++; ...