If you are going to time one of my implementations, I'd really prefer
you time the second one rather than the first one. It's approximately
1500 times faster.
To save you from having to reread my post, here's the implementation:
require'stats'
perms=: A.&i.~ !
,10#.(perms 3){"1/1+3 comb 9
Thanks,
--
Raul
On Mon, Aug 14, 2017 at 4:00 PM, 'Mike Day' via Programming
<[email protected]> wrote:
> Yes, much better!
>
> cf my suggestion a few days ago, and another constructive one using
> tap and comb, q_tap_comb :
>
> ... time & space for Skip's original problem:
> ts'10 #.(,/@:(],"1 0 -."1)^:2 ,.)>:i.9'NB. AG
> 0.000120949 40448
>
> ts'10#.(#~(-:~.)"1) >: 9#.inv i. 9^3' NB. MD
> 0.000774292 84608
>
> ts'q_tap_comb 3' NB. constructive, eg RM
> 0.00130777 39424
>
> ... generating required numbers in [12345, 98765]:
> ts'10 #.(,/@:(],"1 0 -."1)^:4 ,.)>:i.9'
> 0.00548052 2.23386e6
>
> ts'10#.(#~(-:~.)"1) >: 9#.inv i. 9^5'
> 0.066979 5.91731e6
>
> ts'q_tap_comb 5'
> 0.0397513 2.11584e6
>
> where
> q_tap_comb =: tap @[ ,@(10 #."1 {&.:|:) >:@comb&9 f.
> ie
> q_tap_comb
> (i.@! A. i.)@[ ,@(10 #."1 {&.:|:) >:@(4 : 0)&9
>
> k=. i.>:d=.y-x
>
> z=. (d$<i.0 0),<i.1 0
>
> for. i.x do. z=. k ,.&.> ,&.>/\. >:&.> z end.
>
> ; z
>
> )
>
>
> Thanks,
> Mike
>
>
>
> On 14/08/2017 18:16, Arie Groeneveld wrote:
>>
>> My version of variations (without repetitions) :
>>
>> 10 #. (,/@:(],"1 0 -."1)^:2 ,.)1+i.9
>>
>> More general:
>>
>> (3) 4 :'y,/@:(],"1 0 -."1)^:(x-1) ,.y' 'abcd'
>>
>>
>> Op 12-08-17 om 11:16 schreef Skip Cave:
>>>
>>> How can I use J to generate all the possible 3-digit integers that can be
>>> constructed using the digits 1-9 (no zeros), with no repeated digits in
>>> each integer? The sequence starts with 123 (smallest) and goes to 987
>>> (largest). Here's the first few integers in the sequence:
>>>
>>> 123 124 125 126 127 128 129 132 134 135 136 137 138 139 142 143 145 146
>>> 147
>>> 148 149 152 153 154 156 157 158 159 162......
>>>
>>> Skip
>>>
>>> Skip Cave
>>> Cave Consulting LLC
>>> ----------------------------------------------------------------------
>>> For information about J forums see http://www.jsoftware.com/forums.htm
>>
>>
>> ----------------------------------------------------------------------
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>
>
>
>
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