Compilare: main.cpp: In function 'void one()': main.cpp:43:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<G[x].size();i++){ ~^~~~~~~~~~~~ main.cpp: In function 'void two()': main.cpp:63:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<G[x.second.first].size();i++){ ~^~~~~~~~~~~~~~~~~~~~~~~~~