His version is explicit, sort of a C++ translation of the C algorithm (though still a bit longer than necessary even for C). I think he meant to imply "in simple C++ without STL." The awkwardness of partition() is not quite enough to overcome the LOC savings, but it's making a good effort.

The Haskell version also refrains from importing the equivalent Data.List, which would allow us to define `more` and `less` as simply `partition (< x) xs`.