Compilare: user.cpp: In function ‘void mk_next_rand(const std::vector<int>&, std::vector<int>&, const std::vector<std::vector<int> >&, std::vector<bool>&, int&)’: user.cpp:60:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < rand.size(); ++i){ ^ user.cpp: In function ‘int main()’: user.cpp:96:30: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < mat.size(); ++i){ ^ user.cpp:97:34: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j = 0; j < mat[i].size(); ++j){ ^