/in/Compile/check.cpp:85:22: error: use of undeclared identifier 'print_answer'
        submit_ans = print_answer(index);
                     ^
/in/Compile/check.cpp:88:22: error: use of undeclared identifier 'solve'
        submit_ans = solve(grid_copy);
                     ^
2 errors generated.
/in/Compile/Makefile:16: recipe for target 'main' failed
make: *** [main] Error 1