Compilare: user.cpp: In function ‘int bf()’: user.cpp:27:34: 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:44:38: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(f,"%d%d%d%d",&n,&m,&s,&ds); ^ user.cpp:46:43: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(f,"%d%d%d%d",&a,&b,&aa,&bb); ^