foo.cc:11:1: error: ‘f’ does not name a type
   11 | f[mxM+10];   //朴素转移：f[i][j]=max(f[i-1][j], f[i][j-V[i]]+W[i]);现在压缩掉一维空间
      | ^
foo.cc: In function ‘int main()’:
foo.cc:24:25: error: ‘f’ was not declared in this scope
   24 |                         f[j]=max(f[j],f[j-V[i]]+W[i]);
      |                         ^
foo.cc:24:43: error: ‘V’ was not declared in this scope
   24 |                         f[j]=max(f[j],f[j-V[i]]+W[i]);
      |                                           ^
foo.cc:28:15: error: ‘f’ was not declared in this scope
   28 |         cout<<f[m]<<endl;
      |               ^