View Compilation Error

0_0_29977798_20219.cpp: In member function 'bool MFMC::DJ(int&)':
0_0_29977798_20219.cpp:2:12: error: 'first' was not declared in this scope
 #define fi first
            ^
0_0_29977798_20219.cpp:38:10: note: in expansion of macro 'fi'
    int u=fi;
          ^
0_0_29977798_20219.cpp:47:6: error: 'q' was not declared in this scope
      q[e.to]=G[u][i];
      ^
0_0_29977798_20219.cpp: In function 'int main()':
0_0_29977798_20219.cpp:101:24: error: invalid use of 'MFMC::MFMC'
   printf("%d\n",solver.MFMC());
                        ^