@[kakaluo_te](/user/866969)
应该有个特判0吧
by 编码落寞 @ 2022-11-24 09:18:03
看看你前面的那个“警示后人”吧，$0$ 要特判的。
另外，[提问的智慧。](https://studyingfather.blog.luogu.org/how-to-ask-questions-the-smart-way-luogu-edition)
by y_kx_b @ 2022-11-24 09:22:44
@[kakaluo_te](/user/866969)
你少乘了一个二，并且每次多加了一个一，帮你改好了，代码如下
```cpp
#include <stdio.h>
int a[100000] = { 0 };
int main() {
int n;
scanf("%d", &n);
a[1] = 1;
int num=1;
for (int i = 1; i <= n; i++) {
for (int j = 1; j <= num; j++) {
a[j] *= 2;
}
for (int t = 1; t <= num; t++) {
if (a[t] >= 10) {
a[t + 1] += a[t] / 10;
if (num == t) num++;
a[t] %= 10;
}
}
}
a[1]--;
for (int i = num; i >= 1; i--) {
printf("%d", a[i]);
}
return 0;
}
```
by liumuyvan @ 2022-11-24 09:22:58
@[liumuyvan](/user/636097) 其实他的代码没有问题 （$(2^n-1) \times 2 + 1 = 2^{n+1} - 1 $），只是 $2^0-1=0$ 算错了（因为他一开始赋的是1）。
by y_kx_b @ 2022-11-24 09:25:14
@[y_kx_b](/user/592895) 确实，我没有想到~~（我的锅）~~
by liumuyvan @ 2022-11-24 09:32:32
@[y_kx_b](/user/592895) 怎么提问才合适？
by telankesi @ 2022-11-24 11:47:26
@[kakaluo_te](/user/866969) 我只是给个建议。
>怎么提问才合适？
[提问的智慧](https://studyingfather.blog.luogu.org/how-to-ask-questions-the-smart-way-luogu-edition)。
by y_kx_b @ 2022-11-24 12:06:54
@[kakaluo_te](/user/866969) 还不如用py
```
a = int(input())
print(pow(2,a) - 1)
```
by rsy_ @ 2022-11-27 15:58:23