https://adventofcode.com/2021/day/12
For day 12, we had a "cave map" which was a list of connections
between named pairs of rooms.
unpack=:-.&;:&'-';._2
sample=: unpack {{)n
start-A
start-b
A-c
A-b
b-d
A-end
b-end
}}
Here, our puzzle task, for part A, was to explore the cave system. We
needed t
My take on Day 11 followed roughly the same approach, but with a tacit step
function. Likely, the solution verbs a11 and b11 could be made tacit as
well, but as they're so simple, I did not bother.
NB. Day 11: Bioluminescent dumbo octopus flashes
i11=: "."0 ;._2 in 11
NB. how many flashes in 100 s
Hi Mike,
I'm glad my code was useful.
If I recall correctly, I picked up the connected component approach from
how it's implemented in Matlab (
https://nl.mathworks.com/help/images/ref/bwconncomp.html), although I don't
exactly recall whether that uses the shifting. The (excellent) Learning J
book
I like this approach,
Actually, we could ignore 8 (because that's just "all segments"), but
if we are using intersect ([ -. -.) then 8 is our neutral value.
dcnt=:#@~.@-.&' .'@,S:0
unpack=:{{(b#|:y)<@|:/.~b#+/\-.b=.-.*/y=' '}}
digits=:unpack ];._2 {{)n
On Sat, Jan 1, 2022 at 9:28 AM 'Michael Day' via Programming
wrote:
> I can never remember the tessellation idiom when I need it, ...
I have problems with this, also. So I made it a point, during AoC, to
try it out every few days so that my memory could remain fresh.
I tried a variety of exampl
Jan-Pieter,
The use of shifting and padding to produce multiple tables and then operating
on those tables was illuminating to me. I often find myself writing verbs to
process lists and then applying them to tables by transposing or fiddling with
the rank conjunction. For example, this was my s
Solved part 1 similarly.
Not sure if I've got something new for part 2, but my main insight was that
each number is uniquely defined by it's "segment intersections" with the
numbers 1, 4 and 8. Calculating those from a normalized input and applying
them to the left side gives me the numbers represe
At least it's working now.
(Probably the thing to do here would be to fork busybox and ensure
that the fork we use reports errors when files are not unpacked. (I
checked for active development of busybox, and it looks like currently
that is not happening -- instead, I find messages from people hav
Thanks, but before I read your reaction, I installed J903 under 'user' with as
result
JVERSION
Engine: j903/j64avx2/windows
Release-a: commercial/2021-12-16T15:15:09
Library: 9.03.08
Qt IDE: 1.9.5/5.15.2(5.15.2)
Platform: Win 64
Installer: J903 install
InstallPath: c:/users/reb/j903
Contact: w
Yes, the second part was again pretty trivial, at least when, as in
J, you can
use the power operation.
I seem to have solved it on my iPad, running iOS 12.5.5, which is too
obsolete to
support Ian Clark's new J902 version, so it's stuck in J701, so not up
to {{ }} and
lots more.
I can
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