这题其实是字符串处理题，不需要这样做的
by diamond_153 @ 2022-08-20 19:50:51
@[diamond_153](/user/751417) 咋整
by w9121522521l @ 2022-08-30 12:07:22
@[w9121522521l](/user/772892) 递归，先替换成2(n1)+2(n2)+...然后再递归n1,n2...终止条件是n=1或2
by diamond_153 @ 2022-09-01 19:02:14
@[diamond_153](/user/751417) 谢谢大佬
by w9121522521l @ 2022-09-02 23:28:32