Compilare: user.cpp: In function ‘std::vector<std::pair<int, short int> >::iterator search_hash(long long unsigned int)’: user.cpp:28:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(x.code == cod) ^ user.cpp: In function ‘void solve()’: user.cpp:68:18: warning: statement has no effect [-Wunused-value] for(j;j<=M;j++) ^ user.cpp:85:36: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(j=0;j<Hash[i].size();j++) ^