Compilare: user.cpp: In function ‘void update_hash(int)’: user.cpp:21:30: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0; i<h[k].size() && ok==0; i++) ^ user.cpp: In function ‘void delete_hash(int)’: user.cpp:34:30: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0; i<h[k].size(); i++) ^ user.cpp:38:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(i!=h[k].size()-1) ^ user.cpp: In function ‘int query_hash(int)’: user.cpp:50:30: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0; i<h[k].size(); i++) ^