Compilare: user.cpp: In function ‘int bf()’: user.cpp:22:33: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<L[a].size();i++){ ^ user.cpp: In function ‘int main()’: user.cpp:39:22: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(f,"%d",&n); ^ user.cpp:42:30: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(f,"%d",&a); ^