Knight's Challenge in D

[Chris R. Miller]

Tower  Ty Wrote:

> Interesting 
> 
> Your access array is as so
> const int[8][8] access=[
> 	[2, 4, 6, 6, 6, 6, 4, 2],
> 	[4, 6, 8, 8, 8, 8, 6, 4],
> 	[6, 6, 8, 8, 8, 8, 6, 6],
> 	[6, 6, 8, 8, 8, 8, 6, 6],
> 	[6, 6, 8, 8, 8, 8, 6, 6],
> 	[6, 6, 8, 8, 8, 8, 6, 6],
> 	[4, 6, 8, 8, 8, 8, 6, 4],
> 	[2, 4, 6, 6, 6, 6, 4, 2]
> 
> Just taking the first line which explains the side squares of the board I can only see 3 legal moves on each tile you show 4 , and 4 on each tile you show 6. So what am I not seeing ?

What you're seeing is my typo.  I typed that down from memory, something I worked out almost four years ago.  Apparently my memory isn't as good as I'd like it to be.

Now that I look at that matrix, I'm seeing errors that I didn't notice that could significantly change the performance of my algorithm. I'll have to fix that when I get home (and to my compiler).

I think it should be:

const int access[][]= [
    [ 2, 3, 4, 4, 4, 4, 3, 2],
    [ 3, 4, 6, 6, 6, 6, 4, 3],
    [ 4, 6, 8, 8, 8, 8, 6, 4],
    [ 4, 6, 8, 8, 8, 8, 6, 4],
    [ 4, 6, 8, 8, 8, 8, 6, 4],
    [ 4, 6, 8, 8, 8, 8, 6, 4],
    [ 3, 4, 6, 6, 6, 6, 4, 3],
    [ 2, 3, 4, 4, 4, 4, 3, 2]
];

I have the original matrix I used in C fromm all those years ago stored away somewhere.  The defining feature of a good backup is inaccessibility, so it only follows that I can't find it.  Thanks for the catch.  I'll probably patch my algorithm and then only bother to regenerate the SVGs when I get a script to generate the Wiki page as well - last time I had to write in each image link by hand, which wasn't fun.