Showing posts from January 10, 2016

A rather long blast from the past about recursion elimination and a bit of complexity theory

While going through old papers, I found something I wrote as a follow-up to an article by Aaron Banerjee in the February 1999 issue of the world of 68’ micros (you can find a somewhat mangled version online here). Both concern recursion elimination, with the well-known “eight queens” problem (place eight queens on a chess board so that none attacks any other) as an example.
I don’t remember whether I submitted it, or whether it was printed. I’m also embarrassed by the barely legible layout—large Helvetica with nearly no leading. To let me toss the printout and keep the text, and to make it easier to read (if only by me), here it is again, with formatting help from LibreOffice and editing for clarity and concision, not to mention fixing bugs I caused by not directly copying and pasting source code. I will come back and fix indentation on the BASIC09 code, after a little experimentation.
Recursion Elimination and the Eight Queens Problem
In the February 1999 the world of 68’ micros, Aaro…