Roger Hui wrote:
> http://www.jsoftware.com/jwiki/Essays/Knight's_Tour
>
> ktour 8 now much faster, from 470 seconds to 12 seconds.
> Main loop from 17,739,768 iterations to 302,701 iterations.
Even faster:
kt=: 3 : 0
if. 1>:y do. i.,~y return. end.
m=. kmoves y
p=. *:y
stack=. ,&.>|.y (<:/[EMAIL PROTECTED] #&, * +/ ]) i.>.-:y
while. #stack do.
stack=./:~ stack NB. line added
s=. >{:stack
if. a: e. (((i.p)-.s){m)-.&.><s do.
if. (#s)=p-1 do. (,~y)$/:s,(i.p)-.s return. end.
stack=. }:stack continue.
end.
stack=. (}:stack),(<s),&.> s-.~({:s){::m
end.
)
time 'ktour 8'
12.7458
time 'kt 8'
1.53991
Best wishes,
John
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