if (dot_output != nullptr)
fprintf(dot_output, "\"%d\" -> \"%d\" [%s];\n", cur_state->num, next_state->num, req_str.c_str());
if (dot_output != nullptr)
fprintf(dot_output, "\"%d\" -> \"%d\" [%s];\n", cur_state->num, next_state->num, req_str.c_str());