View Compilation Error

0_0_34177727_25301.cpp: In function 'void fmt_or(std::vector<int>&, int, int)':
0_0_34177727_25301.cpp:63:19: error: 'n' was not declared in this scope
     for(int i=0;i<n;++i) for(int j=0;j<len;++j) if(j&(1<<i)) f[j]=(f[j]+op*f[j^(1<<i)]+mod)%mod;
                   ^
0_0_34177727_25301.cpp:63:88: error: 'mod' was not declared in this scope
     for(int i=0;i<n;++i) for(int j=0;j<len;++j) if(j&(1<<i)) f[j]=(f[j]+op*f[j^(1<<i)]+mod)%mod;
                                                                                        ^