On Thu, 04 Jun 2009 09:47:05 -0700, Mensanator wrote: > After all, everybody knows that for m items taken n at a time, the > counts are > > perm w/repl = m**n > comb w/repl = (m+n-1)!/(n!(m-1)!) > perm wo/repl = m!/(m-n)! > comb wo/repl = m!/(n!(m-n)!)
"Everybody" knows? Be careful with those sweeping generalizations. Combinatorics is a fairly specialized area not just of programming but mathematics as well. I've done a spot poll of four developers here (two juniors and two seniors) and *not one* could give all four formulae correctly first go. One guy didn't recognize the terms (although on being reminded, he got two of the four formula). Another one, a self-professed maths-geek, worked them out from first principles. -- Steven -- http://mail.python.org/mailman/listinfo/python-list
