>> I get for this for (222, 9999) --
>> [222, 224, 112, 56, 28, 14, 16, 18, 36, 38, 76, 78, 156, 312, 624,  
>> 1248,
>> 2496, 2498, 4996, 4998, 9996, 19992, 19994, 9997, 9999]
>
> My code dies a horrible death on this one.  <laughs>  I think I get a  
> right answer, but the wait was embarrassing:
>
> $ time ruby numeric_maze.rb 222 9999
> 222, 224, 112, 56, 58, 29, 31, 33, 35, 37, 39, 78, 156, 312, 624,  
> 1248, 2496, 2498, 4996, 4998, 9996, 19992, 19994, 9997, 9999
>
> real    96m13.978s
> user    49m27.502s
> sys     46m22.817s
>
> Guess I need more than my one optimization now.  <laughs>

I stopped at 222 -> 4998 which took 43 seconds. Each next step will take
a rough factor 3, so I'll end up near 3 hours. Oops...

First pruning... Slices running time to less than 0.2 seconds *wheee* and to
9999 in slightly more than 0.2 seconds (which proves I got rid of that nasty
exponential thing).