Compilare: user.cpp: In function ‘int main()’: user.cpp:76:42: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int j = 0; j < sol.size(); ++ j) ^ user.cpp:77:59: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] cout << sol[j] << " \n"[j + 1 == sol.size()]; ^