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
On 7 Dec 2015, at 6:35, David Lambert wrote:
After tracking down the rank error my solution sentence became
+/,on`off`toggle@.({.@identify)"1 A
where A is a matrix containing one instruction per row, and the agenda
item verbs modify a global matrix. Have you guessed my difficulty?
Yes, identify returned a length one vector instead of a scalar.
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