Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!mailrus!csd4.csd.uwm.edu!mrsvr.UUCP!shoreland.uucp!hallett
From: hallett@shoreland.uucp (Jeff Hallett x4-6328)
Newsgroups: comp.graphics
Subject: Re: Tangents to three circles
Message-ID: <902@mrsvr.UUCP>
Date: 22 Aug 89 14:03:19 GMT
References: <11391@polya.Stanford.EDU>
Sender: news@mrsvr.UUCP
Reply-To: hallett@shoreland.UUCP (Jeff Hallett x4-6328)
Organization: GE Medical Systems, Milwaukee,  WI
Lines: 41

In article <11391@polya.Stanford.EDU> rokicki@polya.Stanford.EDU (Tomas G. Rokicki) writes:
>This particular puzzle (given three circles, find all circles tangental
>to these three) was given as a programming puzzle at the 1987 ACM National
>Programming contest.  A correct solution to this puzzle by Bob Alverson
>of the Stanford team helped Stanford take the title that year.  As a
>member of the team, I vaguely recall the solution; it was quite clever.
>It's also not excruciatingly difficult, simply requiring a few insights.
>
>I encourage everyone to try and find an analytical solution before
>reading the spoiler which follows.

Thank you very much Tom.  Your description has shown me the one idea
that I was missing in my solution.  I appreciate your time.

I am forced now to comment on a previous posting...the person asked if
I thought this was a private pool from which I may extract to solve my
personal work problems.  The answer is no, but rather a pool from
which anyone may draw when they have difficulty without fear of
ridicule.  There is a tremendous amount of expertise on the Net, as
demonstrated by Tom, that, without the Net, would never be distributed
to the masses.  It is my feeling that if someone is going to be on the
net, they should be there with the mindset that, if they can pass on
info to help another, they should and that if they need help, they can
ask.  No matter how good someone is, there may come a time when some
small thing escapes them - having a forum like this is a tremendous
benefit for getting objective commentary and insight.

As far as counterexamples go, they are worthwhile when they lead to a
solution of the original problem.  I think that this is the crucial
part missing from the previous poster's tirade.  Just demonstrating
counterexamples, without any other useful information, is demeaning to
someone who may already feel sheepish about asking publicly in the
first place.

Thanks for all the help.

--
                Jeffrey A. Hallett, PET Software Engineering
                    GE Medical Systems, W641, PO Box 414
                            Milwaukee, WI  53201
          (414) 548-5173 : EMAIL -  hallett@positron.gemed.ge.com