Yes, you are right. I misread the question. But I think my solution can be tweaked to get the correct answer:
nr =: 3&=@:#@:~. *. -.@:(0&e.) NB. no repeats, and no zeros allowed. (nr"1 # ] ) 10 10 10 #: i. 1000 I think this gives all permutations with no repeated digits. To integerify the results just do ". (-.&' ')@:":"1 I think your method is nicer though. -------------------------------------------- On Sat, 8/12/17, 'Mike Day' via Programming <programm...@jsoftware.com> wrote: Subject: Re: [Jprogramming] Quora problem To: programm...@jsoftware.com Date: Saturday, August 12, 2017, 8:15 PM I think Skip wants all permutations, not just increasing and decreasing ones, so here's an alternative: 5({.,(-@[){.]) 10#.(#~(3=#@~.)"1) >: 9#.inv i. 9^3 123 124 125 126 127 983 984 985 986 987 The initial 5 ( ) is of course just to limit the output! Any use? Mike On 12/08/2017 10:56, 'Jon Hough' via Programming wrote: > Not particularly efficient or terse but here: > > inc=: -.@:(0&e.)@:~.@:(2&(</\)) NB. increasing > dec=: -.@:(0&e.)@:~.@:(2&(</\)) NB. decreasing > mt=: inc +. dec NB. monotonic > > (-:9*8) }. (mt"1 # ] ) 10 10 10 #: i. 1000 NB. strip off the first 9*4 rows. > -------------------------------------------- > On Sat, 8/12/17, Skip Cave <s...@caveconsulting.com> wrote: > > Subject: [Jprogramming] Quora problem > To: "programm...@jsoftware.com" <programm...@jsoftware.com> > Date: Saturday, August 12, 2017, 6:16 PM > > 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