Date: Sat, 05 Aug 2000 15:36:04 -0400
From: Gary Darby
?/?x?+?x?x?/?+?x?=100 using only 1-9
Here are 3 of 192 solutions (counting commutations) that I found using a program I wrote called "Brute Force".
4/8*6 + 2*5*7/1 + 9*3 = 100
4/1*8 + 2*3*5/6 + 7*9 = 100
6/2*1 + 5*7*8/4 + 3*9 = 100
As the name implies, BruteForce tries all permutations of a given set of integers, substituting into a given set of equations. Works well for problems with no more than a few million possible solutions.
It's written in Delphi (Pascal really), a great learning language. Would also be a great "earning" language if Borland had better marketing skills. It's also too bad that Borland hasn't made it more accessible to young people. I'm currently designing a web site to provide sample puzzle-solving programs for anyone interested in learning Delphi by example. I've registered site names but I still need to convince myself that I want to make the necessary time commitment.
Anyway, I thoroughly enjoy your site. Keep up the good work.