2,4WA同求：
```cpp
#include<bits/stdc++.h>
using namespace std;
int a[21],b[21],c[21];
int n,x,m,y,z,u,ans;
void fibonacci()
{
a[1]=a[2]=1;
for(int i=1;i<=20;i++) a[i]=a[i-1]+a[i-2];
for(int i=1;i<=18;i++) b[i]=a[i]+1;
for(int i=1;i<=19;i++) c[i]=a[i+1]-1;
}
int main()
{
cin>>n>>x>>m>>y;
if(y==1||y==2)
{
cout<<n<<endl;
return 0;
}
if(y==3)
{
cout<<n+n<<endl;
return 0;
}
if(y==x)
{
cout<<m<<endl;
return 0;
}
fibonacci();
z=n;
n*=b[x-2];
m-=n;
u=m/(c[x-1]-b[x-2]);
ans=n*b[y-2]+u*c[y-1];
cout<<ans;
return 0;
}
```
by Phigros_Guest @ 2023-07-06 10:21:48
@[Phigros_Guest](/user/327281)
样例输出18（悲
估计是特判过了
by Phigros_Guest @ 2023-07-06 10:24:54
@[Phigros_Guest](/user/327281)
但是只有特判骗分是4个WA
by Phigros_Guest @ 2023-07-06 10:26:46