exercise: partition a list by equivalence

[Xah Lee]

I started to collect i believe the 4 or so solutions by different
people... but seems it's gonna take some an hour or more... So far the
only other one i've run and find alright is Reinhold Birkenfeld's
original. Others worth noting i'm aware of is David Epsteinn, improved
versions from Reinhold Birkenfeld, the one using graphs by bearophile
...

since many of you have already collected and tested these... i wonder
if anyone'd be interested to put together all the (working) code in a
single message? (or even a webpage.)

thanks.

 Xah
 xah at xahlee.org
 http://xahlee.org/PageTwo_dir/more.html