I’ve just got going on this after throwing in the towel on 23.2, though I haven’t yet persuaded myself to crib your post on that one!
It’s one of those days where Dyalog APL’s direct definitions, where alpha and omega are the default arguments, would have saved renaming the registers to upper case or an alternative set of letters. They were a bit cheeky with only using w with inp, given toy examples including x and z as arguments for inp. My data has, of course, 14 inp ops; to my surprise these were ops 0 18 36 ... Tabulating the data as 14 boxes of 18 ops, the ops and first arguments were identical in each box; I think this applies to all those second arguments which were registers. The only differences were between corresponding integer constants. So, as there’s a sort of paradigm for a set of 18 operations, I’m hoping to be able to analyse that. I’ve just noticed your remark about 26. Presumably there’s going to be an alphabetical aspect to the output. Cheers, Mike Sent from my iPad > On 13 Jan 2022, at 22:17, Raul Miller <rauldmil...@gmail.com> wrote: > > https://adventofcode.com/2021/day/24 > > I have not completed the day 24 puzzle. > > The day 24 puzzle has a sequence of instructions representing a > calculation to verify a model number (and conceptually enable features > based on that model number -- though part A of the puzzle does not > provide any details about that). > > The processing unit performs integer calculations, and has four > registers: W, X, Y and Z. > > There are six instructions, one which inputs a digit of the model > number, an add instruction, a multiply instruction, an integer > division instruction, a modulo instruction and an equals instruction. > > The input instruction always inputs to register W (and is the only > instruction used to update W). The div instruction always divides by 1 > or 26. The modulo instruction is always used to find a remainder > modulo 26 (and always only operates on positive values, or 0 for the > numerator). The multiply instruction seems to always multiply by 0 or > powers of 26. (To load a value into a register, the register is first > multiplied by 0 and then has another value added to it.) > > A certain amount of simplifications are possible using math identities > and range constraints. But I do not have much more that's useful to > say until I've found a way of solving the puzzle. > > Here's a snapshot of where I'm at, trying to work through these issues > (looks sloppy with a proportionally spaced font): > > ... > digit13 NB. W234=: W216 inp 13 [ 1 thru 9 > 0 NB. X235=: X223 mul 0 [ 0 > add Z228 Y232 NB. X236=: X235 add Z233 [ 9 thru 5520918021 > mod 26|Z233 26 NB. X237=: X236 mod 26 [ 0 thru 25 > mul <.Z210%26 X223 NB. Z238=: Z233 div 26 [ 0 thru 212343000 > add X237 _4 NB. X239=: X237 add -4 [ _4 thru 21 > eql X239 digit13 NB. X240=: X239 eql W234 [ 0 thru 1 > eql X240 0 NB. X241=: X240 eql 0 [ 0 thru 1 > 0 NB. Y242=: Y232 mul 0 [ 0 > 25 NB. Y243=: Y242 add 25 [ 25 > mul 25 X241 NB. Y244=: Y243 mul X241 [ 0 thru 25 > add Y244 1 NB. Y245=: Y244 add 1 [ 1 thru 26 > mul <.Z228%26 Y245 NB. Z246=: Z238 mul Y245 [ 0 thru 5520918000 > 0 NB. Y247=: Y245 mul 0 [ 0 > digit13 NB. Y248=: Y247 add W234 [ 1 thru 9 > add digit13 7 NB. Y249=: Y248 add 7 [ 8 thru 16 > mul Y249 X241 NB. Y250=: Y249 mul X241 [ 0 thru 16 > add Z246 Y250 NB. Z251=: Z246 add Y250 [ 0 thru 5520918016 > > I am currently working on some tree unification mechanisms (maximum > common subtree elimination to let me better inspect the partially > resolved calculations). > > I believe Eugene Nonko has solved this one, though I do not know if he > found J useful in his approach. > > FYI, > > -- > Raul > ---------------------------------------------------------------------- > For information about J forums see http://www.jsoftware.com/forums.htm ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
