Compilare: user.cpp: In function ‘void solve()’: user.cpp:164:33: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < sol1.size(); i++) ^ user.cpp:171:33: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < sol2.size(); i += 4) ^ user.cpp: In function ‘int main()’: user.cpp:207:25: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (sol.size() / 4 <= k && sol.size() > 0) ^ user.cpp:210:33: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < sol.size(); i++) ^