On 27/08/2014 14:33, Beat Cornaz wrote:
So, getting rid of the duplicates inside the script is quite important. I still
don't see yet how I can do that in Geoff's script (I will look into that again,
as soon as I can find a little time). If we can get that to work, I think we'll
have a winner :-)
OK, I confess I haven't been following this thread properly.
I tried to go read it all in Nabble, and failed - so my understanding
is, erm, incomplete :-)
But I think the problem is to create all permutations of a set of input
chars, and deal with duplicates.
So here (below) is my version (or rather, my two versions ...)
pSimple() is the simple, obvious recursive function.
It works, doesn't handle duplicates (so that would need to be done as a
post-process, as discussed earlier) - and it's pretty slow; takes 43729
msecs for 10 characters, exactly the same time with duplicates
permut() is the optimized version - optimize simepl cases of 1 or 2
chars, eliminate duplicates as we go.
It works, in the no-duplicate case ("abcdefghij") it takes 23057 msecs
in the mildly duplicate case ("abcdabcdab") it takes 193 msecs
and in the heavily duplicate case ("abbbbbbbbb") it takes < 1 msec
To make it faster, it *should* be serialized, so that it isn't actually
recursive; that should be quite easy (but will make the code much less
easy to read or understand, so I haven't done it yet). If you think
it's worth pursuing, let me know and I'll have a go at unrolling the
recursiveness.
-- Alex.
function pSimple pMute
if the number of chars in pMute = 1 then return pMute
put empty into t3
repeat with i = 1 to the number of chars in pMute
put char i of pMute into c
put pMute into temp
delete char i of temp
put pSimple(temp) into t2
repeat for each line L in t2
put c & L & CR after t3
end repeat
end repeat
return t3
end pSimple
function permut pMute
if the number of chars in pMute = 1 then return pMute
if the number of chars in pMute = 2 then
return pMute & CR & char 2 of pMute & char 1 of pMute
end if
put empty into t3
put empty into tDone
repeat with i = 1 to the number of chars in pMute
put char i of pMute into c
if c is among the chars of tDone then next repeat
put c after tDone
put pMute into temp
delete char i of temp
switch the the number of chars in temp
case 1
put temp into t2
break
case 2
put temp & CR & char 2 of temp & char 1 of temp into t2
break
default
put permut(temp) into t2
end switch
repeat for each line L in t2
put c & L & CR after t3
end repeat
end repeat
return t3
end permut
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