Compilare: user.cpp: In function ‘bool isin(std::pair<int, int>, std::vector<std::pair<int, int> >)’: user.cpp:21:28: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<A.size()-1;++i) ^ user.cpp: In function ‘void make()’: user.cpp:29:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0;i<P.size();++i)if(isin(P[i],Q))R.push_back(P[i]); ^ user.cpp:30:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0;i<Q.size();++i)if(isin(Q[i],P))R.push_back(Q[i]); ^ user.cpp: In function ‘void melk()’: user.cpp:40:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=3;i<R.size();++i) ^ user.cpp:47:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i=0;i<D.size();++i) ^