Me Too.
我甚至都不知道怎么改
by chen_zhe_zhe @ 2022-02-03 09:01:30
模意义下除法不能这么做
by 514InParadox @ 2022-02-03 09:07:57
```cpp
#include<bits/stdc++.h>
using namespace std;
int n;
const int mod=1000000007;
long long ans[100005];
int main() {
cin >> n;
ans[0]=1;
ans[1]=1;
for (int i=2;i<=n;i++) {
for (int j=1;j<=i;j++) {
ans[i]+=((ans[j-1]%mod)*(ans[i-j]%mod))%mod;
}
}
cout << ans[n] << endl;
return 0;
}
```
by chen_zhe_zhe @ 2022-02-03 09:15:51
@[always_first](/user/533125) $\Theta(n^2)$ 过不了，别害人了
by xueruo @ 2023-06-02 19:55:47