Got a bit better C++ version here which uses a couple libraries instead of std:: stuff - https://gist.github.com/jcelerier/74dfd473bccec8f1bd5d78be5a... ; boost, fmt and https://github.com/martinus/robin-hood-hashing

    $ g++ -I robin-hood-hashing/src/include -O2 -flto -std=c++20 -fno-exceptions -fno-unwind-tables -fno-asynchronous-unwind-tables -lfmt

    $ time ./a.out < kjvbible_x10.txt > /dev/null
    0,19s user 0,01s system 99% cpu 0,197 total

with the same build flags, optimize.cpp gives me

    0,22s user 0,01s system 99% cpu 0,233 total