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#!/usr/bin/env BQN
#
# Utilities
#
IsAsciiNum ← ('0'⊸≤∧≤⟜'9')
ReadInt ← {(𝕨⊸×+⊣)´∘⌽-⟜'0'𝕩} # stolen from leah2
ReadDec ← 10⊸ReadInt
ReadInput ← {•file.Lines ∾ •path‿"/input/day"‿(•Fmt 𝕩)}
SplitOn ← ((⊢ (-1˙)⍟⊣¨ +`)∘=⊔⊢)
_fix ← {𝕩 𝕊∘⊢⍟≢ 𝔽 𝕩}
#
# 2021-12-01
#
# part 1
day1ExampleInput ← 199‿200‿208‿210‿200‿207‿240‿269‿260‿263
day1Input ← ReadDec¨ReadInput 1
# NB: Because distance from the ground is never smaller than zero, it's
# no problem that nudge inserts a zero at the end of the right list
PositiveDeltaCount ← +´∘(⊢<«)+˝˘∘↕
! 7 = 1 PositiveDeltaCount day1ExampleInput
•Out "Day 1.1: "∾•Fmt 1 PositiveDeltaCount day1Input
# part 2
! 5 = 3 PositiveDeltaCount day1ExampleInput
•Out "Day 1.2: "∾•Fmt 3 PositiveDeltaCount day1Input
#
# 2021-12-02
#
# part 1
day2ExampleInput ← ⟨
"forward 5",
"down 5",
"forward 8",
"up 3",
"down 8",
"forward 2",
⟩
day2Input ← ReadInput 2
ParseSubmarineCommand ← (((↕2)⊸((((-1)⊸⋆)∘(2⊸|))×(=⟜(⌊∘(÷⟜2))))∘("duf"⊸⊐)∘⊑)×ReadDec∘(IsAsciiNum/⊢))
SubmarineDestProduct ← {×´+´ParseSubmarineCommand¨𝕩}
! 150 = SubmarineDestProduct day2ExampleInput
•Out "Day 2.1: "∾•Fmt SubmarineDestProduct day2Input
# part 2
SubmarineAimedDestProduct ← {
×´+´((×´)∘(1⊸↓)≍(1⊸⊑))¨ (<0‿0‿0) (⊢∾((⊑∘⌽⊣)+(⊑⊢)))` ParseSubmarineCommand¨𝕩
}
! 900 = SubmarineAimedDestProduct day2ExampleInput
•Out "Day 2.2: "∾•Fmt SubmarineAimedDestProduct day2Input
#
# 2021-12-03
#
BinTable ← '0'-˜>
day3ExampleInput ← BinTable ⟨
"00100",
"11110",
"10110",
"10111",
"10101",
"01111",
"00111",
"11100",
"10000",
"11001",
"00010",
"01010",
⟩
day3Input ← BinTable ReadInput 3
DeBinList ← ((2⊸×)+⊣)´⌽
_tableAggr ← {((÷⟜2)∘(/⟜⥊)´∘⌽∘≢𝔽(+˝))𝕩}
GammaRate ← < _tableAggr
! 22 = DeBinList GammaRate day3ExampleInput
! 9 = DeBinList ¬GammaRate day3ExampleInput
•Out "Day 3.1: "∾•Fmt (¬×○DeBinList⊢) GammaRate day3Input
_lifeSupportRating ← {
# Need to rename the arguments, otherwise the ternary expr becomes a function
bitPos ← 𝕨
Cmp ← 𝔽
crit ← Cmp _tableAggr 𝕩
matchPos ← bitPos ⊑˘ crit ((⥊˜⟜≢)=⊢) 𝕩
match ← matchPos/𝕩
{1=≠match?⊏match;(bitPos+1) Cmp _lifeSupportRating match}
}
OxygenGeneratorRating ← DeBinList 0 ≤_lifeSupportRating ⊢
CO2ScrubberRating ← DebinList 0 >_lifeSupportRating ⊢
! 23 = OxygenGeneratorRating day3ExampleInput
! 10 = CO2ScrubberRating day3ExampleInput
•Out "Day 3.2: "∾•Fmt (OxygenGeneratorRating×CO2ScrubberRating) day3Input
#
# 2021-12-07
#
# part 1
day6ExampleInput ← ⟨16,1,2,0,4,2,7,1,2,14⟩
day6Input ← ReadDec¨ ',' SplitOn ⊑ReadInput 6
PossiblePositions ← (⌊´+⟜(↕1⊸+)⌈´)
FuelConsumption ← +˝∘|∘(-⌜)
_lowestFuelPossible ← {⌊´∘(𝔽⟜PossiblePositions)˜ 𝕩}
! 37 = FuelConsumption _lowestFuelPossible day6ExampleInput
•Out "Day 7.1: "∾•Fmt FuelConsumption _lowestFuelPossible day6Input
# part 2
TriNum ← 1⊸+×÷⟜2
FuelConsumption2 ← +˝∘(TriNum¨)∘|∘(-⌜)
! 168 = FuelConsumption2 _lowestFuelPossible day6ExampleInput
•Out "Day 7.2: "∾•Fmt FuelConsumption2 _lowestFuelPossible day6Input
#
# 2021-12-09
#
# part 1
ParseHeightMap ← ((≠≍(≠⊑))⥊∾)∘-⟜'0'
day9ExampleInput ← ParseHeightMap ⟨
"2199943210",
"3987894921",
"9856789892",
"8767896789",
"9899965678"
⟩
day9Input ← ParseHeightMap ReadInput 9
Rotate ← (⍉⌽)∘⊢⍟⊣ # counter clockwise
LowPoints ← {∧´𝕩⊸(⊣<((-⊢) Rotate ∞⊸»˘∘Rotate˜))¨ ↕4}
RiskLevelSum ← (+´⥊)∘(1⊸+×LowPoints)
! 15 = RiskLevelSum day9ExampleInput
•Out "Day 9.1: "∾•Fmt RiskLevelSum day9Input
# part 2
NumberBasins ← ((1⊸+⊒⌾⥊)×⊢)∘LowPoints
Basins ← {𝕩⊸((<⟜9⊣)∧(«⌈»⌈«˘⌈»˘⌈⊢)∘⊢) _fix NumberBasins 𝕩}
LargestBasinsProduct ← {×´ 3↑ ∨ 1↓ ≠¨ ⊔⥊Basins 𝕩}
! 1134 = LargestBasinsProduct day9ExampleInput
•Out "Day 9.2: "∾•Fmt LargestBasinsProduct day9Input
#
# 2021-12-13
#
SplitFoldingInstructions ← ("fold along"⊸(⊣≡≠⊸↑)¨⊔⊢)∘(0⊸(≠⟜≠¨/⊢))
day13ExampleInput ← SplitFoldingInstructions ⟨
"6,10",
"0,14",
"9,10",
"0,3",
"10,4",
"4,11",
"6,0",
"6,12",
"4,1",
"0,13",
"10,12",
"3,4",
"3,0",
"8,4",
"1,10",
"2,14",
"8,10",
"9,0",
"",
"fold along y=7",
"fold along x=5",
⟩
day13Input ← SplitFoldingInstructions ReadInput 13
ParseDots ← ReadDec¨∘(','⊸SplitOn)¨
ParseFolds ← (⊑∘'y'⊸∊≍ReadDec∘(IsAsciiNum/⊢))¨
day13ExampleDots ← ParseDots ⊑ day13ExampleInput
# part 1
# 𝕨=0 => x, 𝕨=1 => y
# 𝕩 is coordinate to fold around
# 𝕗 is input dot list (see ParseDots)
_Fold ← {⍷∘((𝕩⊸(((2⊸×⊣)-⊢)⌊⊢)∘⊑≍1⊸⊑)¨⌾(⌽¨⍟𝕨)) 𝕗}
! 17 = ≠ 1 day13ExampleDots _Fold 7
day13Dots ← ParseDots ⊑ day13Input
day13Folds ← ParseFolds 1 ⊑ day13Input
•Out "Day 13.1: "∾•Fmt ≠ (day13Dots _Fold)´ ⊑day13Folds
# part 2
PerformAllFolds ← {𝕩 {(𝕨 _Fold)´𝕩}˜´ ⌽𝕨}
DotMatrix ← {
⟨width, height⟩ ← 1+⌈˝∘‿2⥊∾𝕩
{𝕩? '█';' '}¨ height‿width⥊≠¨⊔((⊣+(width⊸×)∘⊢)´)¨ 𝕩
}
•Out "Day 13.2:"
•Out •Fmt DotMatrix day13Folds PerformAllFolds day13Dots
#
# 2021-12-14
#
day14Polymer ← ⊑ReadInput 14
day14Mapping ← 2↓ReadInput 14
lp ← (2⊸↑)¨ day14Mapping
le ← ⍷∾lp
# returns array as long as 𝕨 detailing how many times the element
# at any given index occurs in 𝕩.
Counts ← ((≠⊣)↑(/⁼)∘⊐)
deltaPairs ← {
addedPairs ← ((-1)⊸⊑¨day14Mapping) (⌽⌾(0⊸⊑))∘(∾¨)¨ lp
removedPairs ← ⋈¨ (2⊸↑)¨ lp
addedPairs (-○(lp⊸Counts))¨ removedPairs
}
pairCount ← lp Counts ⥊∘(⋈˘) 2↕day14Polymer
PairInsert ← {𝕩 +´ 𝕩רdeltaPairs}
pairElementCount ← (le⊸Counts)¨lp
ElementRarityDiff ← {
((-1)⊸⊑-⊑)∧ ⌈2÷˜ +´ pairElementCount×PairInsert⍟𝕩 pairCount
}
•Out "Day 14.1: "∾•Fmt ElementRarityDiff 10
•Out "Day 14.2: "∾•Fmt ElementRarityDiff 40
#
# 2021-12-15
#
day15ExampleInput ← >⟨
1‿1‿6‿3‿7‿5‿1‿7‿4‿2
1‿3‿8‿1‿3‿7‿3‿6‿7‿2
2‿1‿3‿6‿5‿1‿1‿3‿2‿8
3‿6‿9‿4‿9‿3‿1‿5‿6‿9
7‿4‿6‿3‿4‿1‿7‿1‿1‿1
1‿3‿1‿9‿1‿2‿8‿1‿3‿7
1‿3‿5‿9‿9‿1‿2‿4‿2‿1
3‿1‿2‿5‿4‿2‿1‿6‿3‿9
1‿2‿9‿3‿1‿3‿8‿5‿2‿1
2‿3‿1‿1‿9‿4‿4‿5‿8‿1
⟩
day15Input ← '0'-˜ ((≠⋈≠∘⊑)⥊∾)ReadInput 15
LowestRiskLevel ← {
start ← 0˙⌾⊑ (⥊⟜∞) ≢𝕩
ir ← (1⊑≢𝕩)⥊∞
Step ← {𝕩 ⌊ 𝕨 + (ir⊸«⌊ir⊸»⌊∞⊸«˘⌊∞⊸»˘) 𝕩}
⊑⌽⥊ 𝕩⊸Step _fix start
}
! 40 = LowestRiskLevel day15ExampleInput
•Out "Day 15.1: "∾•Fmt LowestRiskLevel day15Input
FiveByFiveMap ← {(9⊸|)⌾(-⟜1) ∾(<𝕩)+ +⌜˜↕5}
! 315 = LowestRiskLevel FiveByFiveMap day15ExampleInput
•Out "Day 15.2: "∾•Fmt LowestRiskLevel FiveByFiveMap day15Input
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