Compilare: user.cpp: In member function ‘void sum_aib::update(int, int, int)’: user.cpp:20:42: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int xx = x; xx >= 0 && xx < v.size(); xx += (xx+1)&(-xx-1)){ ^ user.cpp:21:43: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int yy = y; yy >= 0 && yy < v.size(); yy += (yy+1)&(-yy-1)){ ^ user.cpp: In member function ‘int sum_aib::query(int, int)’: user.cpp:26:42: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int xx = x; xx >= 0 && xx < v.size(); xx -= (xx+1)&(-xx-1)){ ^ user.cpp:27:43: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int yy = y; yy >= 0 && yy < v.size(); yy -= (yy+1)&(-yy-1)){ ^