@[f_hxr_](/user/754467) 缺了2个空格
```cpp
#include<bits/stdc++.h>
using namespace std;
long long f[25][25][25],a,b,c;
long long w(long long x,long long y,long long z){
if(x<=0||y<=0||z<=0)
return 1;
else if(x>20||y>20||z>20)
return w(20,20,20);
else if(f[x][y][z]!=-1)
return f[x][y][z];
else if(x<y&&y<z)
return f[x][y][z]=w(x,y,z-1)+w(x,y-1,z-1)-w(x,y-1,z);
else
return f[x][y][z]=w(x-1,y,z)+w(x-1,y-1,z)+w(x-1,y,z-1)-w(x-1,y-1,z-1);
}
int main(){
memset(f,-1,sizeof(f));
while(scanf("%lld%lld%lld",&a,&b,&c)==3){
if(a==-1&&b==-1&&c==-1)break;
cout<<"w("<<a<<','<<' '<<b<<','<<' '<<c<<") = ";
if(a>20)a=21;
if(b>20)b=21;
if(c>20)c=21;
//cout<<a<<" "<<b<<" "<<c<<" "<<endl;
cout<<w(a,b,c)<<endl;
}
return 0;
}
```
by xiaoming007 @ 2023-04-03 20:27:54
@[xiaoming007](/user/938449) 已A，谢谢QWQ
by f_hxr_ @ 2023-04-03 20:30:04