v[i][j]=a[i][j]; 这一行错了，应当是b[x+j][y-i]=a[x+i][y+j];
by 1234567890hh @ 2023-07-03 07:23:19
不对：
```cpp
for(int j = y-r;j <= y+r;i++)
for(int j = y-r;j <= y+r;i++)
```
by keven_wang @ 2023-08-09 18:24:30
i++ 改成 j++
by keven_wang @ 2023-08-09 18:24:55