mem size   v5.26.0   v5.24.2   v5.22.4   cperl
optimized i2   1,326 MB   31 secs   32 secs   33 secs   30 secs
2 nums into 1  1,292 MB   33 secs   34 secs   35 secs   31 secs
shorter impl   1,443 MB   35 secs   36 secs   37 secs   31 secs