Compilare: user.cpp: In member function ‘void sol::print_periods()’: user.cpp:91:41: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j=0;j<p[i].size();j++) { ^ user.cpp:97:35: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<pp.size();i++) { ^ user.cpp: In member function ‘void sol::solve()’: user.cpp:107:34: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<v.size();i++) { ^ user.cpp:108:21: warning: unused variable ‘u’ [-Wunused-variable] int u = 0; ^