/* _s stands for s, _ns not sorted */
template<typename IT,typename sz>
bool full_col_persistence(IT r1_s,IT r2_s,IT r1_ns,IT r2_ns,sz cols_to_compare) {
    while(cols_to_compare > 0) {
        IT&& r1_temp_cpy  {r1_s};
        IT&& r2_temp_cpy  {r2_s};