$f(n)=\begin{cases} 1 \quad(n=1) \\ 2 \quad (n=2) \\
f(n-1)+f(n-2) \ (n>2)\end{cases}$
代码应该很好写啊
by Celestial_Scarlet @ 2019-05-24 20:47:54
这不就是个斐波那契吗(大雾弥漫
by 豌豆射手皮0608 @ 2019-05-24 20:47:55
我……
$ f(n)=\begin{cases} 1 \quad (n=1) \\ 2 \quad (n=2) \\ f(n-1)+f(n-2) \ (n>2) \end{cases} $
再炸我女装
by Celestial_Scarlet @ 2019-05-24 20:49:10
@[TCZN](/space/show?uid=108361) 求数据范围
by Celestial_Scarlet @ 2019-05-24 20:49:56
@[baoyu](/space/show?uid=93465) 蒟蒻做不到啊，跪求代码或伪程序
by TCZN @ 2019-05-24 20:50:19
@[baoyu](/space/show?uid=93465) 正常范围
by TCZN @ 2019-05-24 20:50:44
[里面都有(](https://www.luogu.org/problemnew/show/P4000)
by 豌豆射手皮0608 @ 2019-05-24 20:51:12
@[TCZN](/space/show?uid=108361) 正常范围是啥意思啊
$n \leq 10^6$ 写个简单的就行了，但 $n \leq 10^{18}$ 的话我还要放个矩阵优化上来
by Celestial_Scarlet @ 2019-05-24 20:51:38
@[baoyu](/space/show?uid=93465) 那就简单的
by TCZN @ 2019-05-24 20:52:12
$10^{30000000}$可正常了(大雾弥漫
by 豌豆射手皮0608 @ 2019-05-24 20:52:19