开 ```long long``` 试试。
by Strelitzia_ @ 2022-07-17 13:22:11
@[Jesusdalao](/user/701230) $N \le 18$, 您这只处理到 $N = 15$.
by JackMerryYoung @ 2022-07-17 13:22:42
@[Jesusdalao](/user/701230) 数据是$n\le 18$，循环到 18 不是 15
by ssxvngn @ 2022-07-17 13:23:11
@[Jesusdalao](/user/701230) 还有要开 `long long`.
by JackMerryYoung @ 2022-07-17 13:23:26
好哒，Thanks♪(･ω･)ﾉ
by Jesusdalao @ 2022-07-17 13:31:12
点击查看题解：https://oj.mimadao.com/submission/571383
by Xiaonanu @ 2022-08-23 13:12:24
代码
```
#include<bits/stdc++.h>
using namespace std;
int f[20];
int main(){
f[0]=1,f[1]=1,f[2]=2;
for(int i=3;i<=18;i++){
for(int j=0;j<=i-1;j++){
f[i]+=f[j]*f[i-j-1];
}
}
int n;
cin>>n;
cout<<f[n]<<endl;
return 0;
}
```
by zhangjiting @ 2022-11-09 09:26:15
十年OI一场梦，不开long long见祖宗
要开long long
by 翟俊斐2012 @ 2022-11-09 20:53:01