Compilare: user.cpp: In function ‘void solve(std::vector<int>&, std::vector<int>&)’: user.cpp:16:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < st.size() / 2; ++i) ^ user.cpp:27:32: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = st.size() / 2; i < st.size(); ++i) ^ user.cpp:42:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < sol_a.size(); ++i) ^ user.cpp:48:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < sol_a.size(); ++i) ^ user.cpp: In function ‘int main()’: user.cpp:79:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < sir.size(); ++i) ^