A little late, but mine appears to be similar day1a =: [: +/ "."0 @ (] #~ 1&|. = ])
day1b =: [: +/ "."0 @ (] #~ (|.~ (2%~#)) = ]) assert 3 -: day1a '1122' assert 4 -: day1a '1111' assert 6 -: day1b '1212' assert 4 -: day1b '123425' assert 12 -: day1b '123123' assert 4 -: day1b '12131415' On Fri, Dec 1, 2017 at 2:22 AM, robert therriault <[email protected]> wrote: > Nice explanation Daniel, > > Tacit with hooks! > > Xmas1t=: +/@#~ (= 1&|.) > Xmas2t=: +/@#~ (= -:@$ |. ]) > > Cheers, bob > > > > On Nov 30, 2017, at 10:43 PM, 'Pascal Jasmin' via Programming < > [email protected]> wrote: > > > > tacit just enough to avoid repetition > > > > +/ (#~ ] = 1 |. ] ) a > > +/ (#~ ] = -:@# |. ] ) a > > > > > > > > > > ________________________________ > > From: Daniel Lyons <[email protected]> > > To: [email protected] > > Sent: Friday, December 1, 2017 12:49 AM > > Subject: [Jprogramming] Advent of Code, Day 1 (spoilers) > > > > > > > > The problem statement has to do with summing up digits in a large number > if the digit matches the following digit, with wraparound. > > > > > > My concept is to take the input as an array of single-digit numbers, > compare this to itself rotated forward a digit. Wherever those match up, > the following digit is a match. I can then copy to select the values that > match and then simply sum them up. It works out like this: > > > > > > NB. First I want digits, so: > > > > a =. "."0 '<my big captcha string>' > > > > > > NB. Part 1: the idea is to line up the input against itself, rotated > right one > > > > +/ a #~ a = 1 |. a > > > > > > This worked, and then the twist in problem 2 turned out to be easy to > compensate for: instead of hard-coding 1, calculate half the length of the > array: > > > > > > NB. Part 2: rotate by half the length > > > > +/ a #~ a = (-: $ a) |. a > > > > > > I did not even try to define these as functions, since I was sure I'd > lose the plot trying to make them tacit and get frustrated. > > > > > > -- > > > > Daniel Lyons > > > > > > > > > > > > ---------------------------------------------------------------------- > > > > For information about J forums see http://www.jsoftware.com/forums.htm > > ---------------------------------------------------------------------- > > For information about J forums see http://www.jsoftware.com/forums.htm > > ---------------------------------------------------------------------- > For information about J forums see http://www.jsoftware.com/forums.htm > ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
