如果输入 100000 呢？
by ud2_ @ 2021-12-07 21:32:07
@[21csy](/user/632495) 用 `int` 存储 $10^5\times(10^5-1)\times(10^5-2)\times(10^5-3)\over24$ 试试不就逝世
by DaShaber @ 2021-12-07 21:32:16
一次性求积太大了，可以用数学方法优化
by ScottSuperb @ 2021-12-07 21:33:35
开
```
unsigned long long
```
就行了
试试
```
long long
```
就逝世
by EntimE @ 2021-12-07 21:37:16
@[21csy](/user/632495)
by EntimE @ 2021-12-07 21:37:43
@[Devsong](/user/437893) 咋转化啊？
by zelei111 @ 2021-12-28 11:00:56
用了long long怎么也不行呢？
by xkg821 @ 2022-01-24 11:45:10
为什么n限制的是10的五次方但是必须要用ull才能过啊?
by jingchuan_Hou @ 2022-04-06 10:47:55