Compilare: user.cpp: In function ‘int main()’: user.cpp:34:24: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0;i<M.size()-1;i++) ^ user.cpp:35:28: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(j=i+1;j<M.size();j++) ^ user.cpp:55:24: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0;i<sol.size();i++) ^