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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
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