Compilare: main.cpp: In function 'bool bell(long long int, long long int)': main.cpp:30:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<l[nod].size();i++){ ~^~~~~~~~~~~~~~ main.cpp:48:1: warning: control reaches end of non-void function [-Wreturn-type] } ^