数三退一

ArrayList list = new ArrayList(); for (int i = 1; i <= 13; i++) { list.add(i); } int a = 1; int b = 0; while (list.size() != 1) { if (a % 3 == 0) { list.remove(b); b--; } else { b++; if (b == list.size()) { b = 0; } } a++; } System.out.println("第" + list.get(0)+"个人剩下了");