```cpp
while(1){
cin>>a>>b>>c
if(a==-1&&b==-1&&c==-1) break;
ll ina=a,inb=b,inc=c;
if(a>20||b>20||c>20){
a=20;
b=20;
c=20;
}
cout<<"w("<<ina<<", "<<inb<<", "<<inc<<")"<<" = "<<w(a,b,c)<<endl;
}
```
给一组hack
```
-1 10 20
```
正确答案：1
你的答案：1048576
by zhouzihang1 @ 2023-08-24 21:36:24
先判断有没有<=0的，在判断有没有>20的
by zhouzihang1 @ 2023-08-24 21:37:15
@[levy2011](/user/990838)
by zhouzihang1 @ 2023-08-24 21:38:08
@[zhouzihang1](/user/827018) 改完了，变成#1 #2 WA
```cpp
#include<bits/stdc++.h>
#define ll long long
using namespace std;
bool vis[21][21][21];
ll v[21][21][21];
ll w(int a,int b,int c){
if(a<=0||b<=0||c<=0) return 1;
if(a>20||b>20||c>20) return w(20,20,20);
else if(vis[a][b][c]) return v[a][b][c];
else if(a<b&&b<c) v[a][b][c]=w(a,b,c-1)+w(a,b-1,c-1)-w(a,b-1,c);
else v[a][b][c]=w(a-1,b,c)+w(a-1,b-1,c)+w(a-1,b,c-1)-w(a-1,b-1,c-1);
vis[a][b][c]=true;
return v[a][b][c];
}
int main(){
ll a=0,b=0,c=0;
memset(vis,false,sizeof(vis));
while(1){
cin>>a>>b>>c;
if(a==-1&&b==-1&&c==-1) break;
cout<<"w("<<a<<", "<<b<<", "<<c<<")"<<" = "<<w(a,b,c)<<endl;
}
return 0;
}
``````
by levy3304 @ 2023-08-24 22:06:00
求指点
by levy3304 @ 2023-08-24 22:06:57
```cpp
else if(vis[a][b][c]) return v[a][b][c];
```
改成
```cpp
else if(v[a][b][c]) return v[a][b][c];
```
试试？
by zhouzihang1 @ 2023-08-25 07:26:56
@[zhouzihang1](/user/827018) 还是#1 #2 WA
by levy3304 @ 2023-08-25 09:26:57
AC了，感谢大佬指点！
by levy3304 @ 2023-08-25 10:24:45