Ryan made a mask shape 1000 1000 and applied it appropriately to a
cumulative array. Pascal updated the accumulation array in place. I did
so likewise but used the dyadic form of amend with gerund m. Pascal
computed the index in one place, which I prefer to my 3 sites.
g
[: r/ [: _&". {::"0 1
r NB. absolute value not required
([ + i.@:|@:(-/)) >:
NB. noun L is the array of lights.
identify NB. whoops! returns a vector
0 1 2 #~ 'turn on'&({.@E.) , 'turn off'&({.@E.) , 'toggle'&({.@E.)
on
3 : 0
I=:([: < 2 6&g ; 4 8&g)@;:y
NB. L=:I (1:)`([)`(])}L
L=:I (>:@:{)`([)`(])}L
EMPTY
)
off
3 : 0
I=:([: < 2 6&g ; 4 8&g)@;:y
NB.I (0:)`([)`(])}L
L=:I ((0>.<:)@:{)`([)`(])}L
EMPTY
)
toggle
3 : 0
I=:([: < (<:2 6)&g ; (<:4 8)&g)@;:y
NB. L=: I (-.@:{)`([)`(])}L
L=:I (2+{)`([)`(])}L
EMPTY
)
NB. what the heck??? Why is this zero?
+/, L [ on`off`toggle@.({.@identify)@,;._2(1!:1)<'/tmp/a' [ L=:1000
1000$0
0
+/,L
14110788
Date: Mon, 07 Dec 2015 08:46:59 +1100
From: "Ryan Eckbo"<ec...@cim.mcgill.ca>
To: programming<programm...@jsoftware.com>
Subject: Re: [Jprogramming] adventofcode 6
Message-ID:<b4007f86-91ad-409c-95d6-ba6d6966c...@cim.mcgill.ca>
Content-Type: text/plain; format=flowed
How do your on/off/toggle functions work? My solution also updates a
global matrix,
but my implementation doesn't feel good. Looking forward to seeing
nicer solutions.
xind=: 3 : 0&{ + [: i. >:@:(-/)@:(2 0&{)
yind=: 3 : 1&{ + [: i. >:@:(-/)@:(3 1&{)
mkmask=: 3 : '1 inds} 1000 1000 $ 0 [ inds=: < (xind y);(yind y)'
on=: 3 : 'lights=: lights + mkmask y'
off=: 3 : 'lights=: 0 >. lights - mkmask y'
toggle=: 3 : 'lights=: lights + +: mkmask y'
instructions=: <;._2 (' through ';',';'turn ';'') stringreplace
fread'/tmp/input.txt'
lights=: 1000 1000$0
do each instructions
+/, lights
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