第一题：static LinkedList<Integer> path = new LinkedList<>(); static int sum = 0; public static boolean method(int N, int c, int[] array, int startIndex) { if (sum==N || (sum<N && sum+c>=N)) { return true; } for (int i = startIndex; i < array.length; i++) { path.add(array[i]); sum += array[i]; boolean res = method(N, c, array, i + 1); if (res){ return res; } path.removeLast(); sum -= array[i]; } return false; }