Compilare: user.cpp: In function ‘int main()’: user.cpp:64:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while(lung<V[0].size() && lung<V[1].size() && V[0][lung].first==V[1][lung].first) ~~~~^~~~~~~~~~~~ user.cpp:64:39: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while(lung<V[0].size() && lung<V[1].size() && V[0][lung].first==V[1][lung].first) ~~~~^~~~~~~~~~~~ user.cpp:67:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=lung; i<V[0].size(); i++) ~^~~~~~~~~~~~ user.cpp:69:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=lung; i<V[1].size(); i++) ~^~~~~~~~~~~~ user.cpp:71:16: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(lung==V[0].size()) ~~~~^~~~~~~~~~~~~ user.cpp:77:16: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(lung==V[1].size()) ~~~~^~~~~~~~~~~~~