foo.cc: In function 'int main()':
foo.cc:44:17: warning: suggest parentheses around '+' inside '<<' [-Wparentheses]
         i==(1<<j+1)&&(++j),hb[i]=j;
                ~^~
foo.cc:58:29: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
             if (t<0) ans=(-t>=a[y].size()?0:a[y][-t]);
                           ~~^~~~~~~~~~~~~
foo.cc:59:24: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
             else ans=(t>=b[y].size()?0:b[y][t]);
                       ~^~~~~~~~~~~~~

[Hydro](https://hydro.ac)提供评测服务