Compilare: main.cpp: In function 'int main()': main.cpp:33:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=1;i<usu.size();++i) ~^~~~~~~~~~~ main.cpp:43:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<sol.size();i++) g<<sol[i]<<' '; ~^~~~~~~~~~~