From 291d84d983f351ac392eeaae615be17e0140db4c Mon Sep 17 00:00:00 2001 From: Alpha Chen Date: Mon, 9 Dec 2024 21:19:36 -0800 Subject: [PATCH] [2024][ruby][10.1] --- 2024/ruby/day_10.rb | 79 +++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 79 insertions(+) create mode 100644 2024/ruby/day_10.rb diff --git a/2024/ruby/day_10.rb b/2024/ruby/day_10.rb new file mode 100644 index 0000000..daca967 --- /dev/null +++ b/2024/ruby/day_10.rb @@ -0,0 +1,79 @@ +map = DATA.readlines(chomp: true).flat_map.with_index {|row, y| + row.chars.map.with_index {|height, x| + [[y,x], height == ?. ? nil : height.to_i] + } +}.to_h + +trailheads = map.filter_map { _2 == 0 && _1} +# trailends = map.select { _2 == 9 } + +DELTAS = [[-1, 0], [1, 0], [0, -1], [0, 1]] + +def trailends(map, head) + queue = [head] + visited = Set.new + until queue.empty? + current = queue.shift + visited << current + + queue.concat( + DELTAS + .map {|d| current.zip(d).map { _1 + _2 } } + .select { map.fetch(_1, nil) == map.fetch(current) + 1 } + .reject { visited.include?(_1) } + ) + end + visited.select { map.fetch(_1) == 9 } +end + +pp trailheads.sum { trailends(map, _1).length } + +__END__ +101987698323656762989721011010987456780121243210 +234012567210547891078892012101072345891030984569 +142103454345432012367743423232161654322345855678 +051054965236701103456656894343450783210496764789 +962167850149896543245765765456980892108587053298 +873076701056787600130876554967821876549652142103 +954987432165634512021989478876782965678703234012 +765876541074328763145672369805493454302212547654 +896968953981019854236981054012349854211243478943 +657857762876567610765100340101238763210798545692 +765446891001498723834232215293045678189877632781 +802335432312387654923341004382167669012368701020 +911124701421019870110056905673458978975459345210 +320099876598943065232167810569898963287561276349 +456787756787854104343054321678107854196510389458 +329878941012763210454988934521256981075431343367 +019561030323678923567867141010345410987123454321 +878432321410589854543252012367894322346001067800 +965678798523470189630141043454387011055432108912 +234309657631063238745632658965296545765443297983 +103210545432154127030745667870101239812344589854 +123451236943061032121836789654320149801256678765 +018760147858978945412921078761012456789107967810 +569676546567167656503832099908901327898798856921 +678989432100016987434512187819832010145610765430 +567010498761221498729603456520743016234431254321 +154321343254330327018777895431654327652342341232 +034501656189945012310689765432343678541056540765 +127652783076876763423676543087652589230767439856 +098743692105677894534589832198101450121858921045 +769878901234786765109689101265012376543929012234 +878963210121099889278770125654321289012210430123 +987654323452016776308765210787430100101121522434 +670122014560125655419654354896508921089037611078 +549831009871234534328323763011017632176548902369 +038742789965676548933214892182126543210423098454 +125653656234987837654300321099234304321012167823 +034564540165832921020311456788765015698143456910 +321078939874981021011232321001298923789874301501 +012981543403876120102345409876387654301565217652 +565470034512985433201456912345401543214321438943 +678321127621076894398567810126918754265410521032 +099128938902345765487656787637829662178345621001 +187019878213765496567678698540134543089210782789 +236520569347874385438569187687238956745432893610 +945431450956901276329430056796549875856721894523 +876532321876101301210321149823456721949890765434 +765321012765432340343434231012545430132101256545