I suggest you use larger numbers for your performance tests. (10#.(#~(-:~.)"1) >: 9#.inv i. 9^6)-: 10 #.(,/@:(],"1 0 -."1)^:5 ,.)>:i.9 1 ts'10#.(#~(-:~.)"1) >: 9#.inv i. 9^6' 0.39192919 1.7905766e8 ts'10 #.(,/@:(],"1 0 -."1)^:5 ,.)>:i.9' 0.010126433 9442816
The Groeneveld solution is more efficient by a factor of approx. 700 (38 * 19). Apart from being the most elegant. R.E. Boss > -----Original Message----- > From: Programming [mailto:programming-boun...@forums.jsoftware.com] > On Behalf Of 'Mike Day' via Programming > Sent: maandag 14 augustus 2017 22:01 > To: programm...@jsoftware.com > Subject: Re: [Jprogramming] Quora problem > > 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 > > > > ---------------------------------------------------------------------- > > For information about J forums see > http://www.jsoftware.com/forums.htm > > > > --- > This email has been checked for viruses by Avast antivirus software. > https://www.avast.com/antivirus > ---------------------------------------------------------------------- > For information about J forums see http://www.jsoftware.com/forums.htm ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
