/in/foo.cc: In function 'int main()':
/in/foo.cc:48:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
       for(tot=0;tot<hv[i].size();++tot) ans[tot]=hv[i][tot];
                 ~~~^~~~~~~~~~~~~
/in/foo.cc:29:20: warning: unused variable 't' [-Wunused-variable]
    int i,j,k,ix,iy,t;
                    ^