Compilare: user.cpp: In function ‘int main()’: user.cpp:22:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < sol.size(); ++ i) ~~^~~~~~~~~~~~ user.cpp:23:45: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] cout << (sol[i] + 1) << " \n"[i + 1 == sol.size()]; ~~~~~~^~~~~~~~~~~~~