From ba719f8f5e8a1bb55a9f4fc99cd0e853f7ec62b8 Mon Sep 17 00:00:00 2001
From: sterni <sternenseemann@systemli.org>
Date: Sun, 18 Dec 2022 16:56:32 +0100
Subject: [PATCH] feat(sterni/aoc/2022): day18 BQN solution

Change-Id: I1504cd5e443ff0b28c2d97ae357e5d92c88bba4d
Reviewed-on: https://cl.tvl.fyi/c/depot/+/7601
Reviewed-by: sterni <sternenseemann@systemli.org>
Tested-by: BuildkiteCI
Autosubmit: sterni <sternenseemann@systemli.org>
---
 users/sterni/exercises/aoc/2021/solutions.bqn |  3 ++-
 users/sterni/exercises/aoc/2022/18/18.bqn     | 14 ++++++++++++++
 users/sterni/exercises/aoc/lib.bqn            |  2 ++
 3 files changed, 18 insertions(+), 1 deletion(-)
 create mode 100644 users/sterni/exercises/aoc/2022/18/18.bqn

diff --git a/users/sterni/exercises/aoc/2021/solutions.bqn b/users/sterni/exercises/aoc/2021/solutions.bqn
index f7247cadf..755c94404 100755
--- a/users/sterni/exercises/aoc/2021/solutions.bqn
+++ b/users/sterni/exercises/aoc/2021/solutions.bqn
@@ -1,5 +1,7 @@
 #!/usr/bin/env BQN
 
+⟨Xor⟩ ← •Import "../lib.bqn"
+
 #
 # Utilities
 #
@@ -469,7 +471,6 @@ _EnhancedPixelCount ← {+´⥊⊑ (𝕨⊸Enhance)⍟𝕗 𝕩}
 day25Input ← ".>v" ⊐ > ReadInput 25
 day25ExampleInput ← ".>v"⊐∘‿10⥊"v...>>.vv>.vv>>.vv..>>.>v>...v>>v>>.>.v.v>v.vv.v..>.>>..v....vv..>.>v.v.v..>>v.v....v..v.>"
 
-Xor ← (¬⊸∧∨∧⟜¬)
 MoveHerd ← {(𝕩∧𝕩≠𝕨)+𝕨× (𝕨=𝕩) (Xor⟜(1⊸⌽)∨⊢) (0=𝕩)∧(-1)⌽𝕨=𝕩}
 
 _fixCount ← {
diff --git a/users/sterni/exercises/aoc/2022/18/18.bqn b/users/sterni/exercises/aoc/2022/18/18.bqn
new file mode 100644
index 000000000..76ec569fe
--- /dev/null
+++ b/users/sterni/exercises/aoc/2022/18/18.bqn
@@ -0,0 +1,14 @@
+lib ← •Import "../../lib.bqn"
+
+i ← (lib.ReadDec¨(<',')⊸lib.SplitOn)¨ •FLines "input"
+dim ← 1+⌈´i
+cubes ← i∊˜↕dim
+
+views ← ⟨0‿1‿2, 1‿2‿0, 2‿0‿1⟩
+Exposed ← {(6×+´⥊𝕩)-2×+´views{+´⥊(∧˝˘)2↕𝕨⍉𝕩}¨<𝕩}
+Interior ← {(¬𝕩)∧´views{((lib.Xor`∘((∊∧⊢)∨»∘(∊⌾⌽∧⊢)))⎉1)⌾(𝕨⊸⍉)𝕩}¨<𝕩}
+Displace ← {⌈´(⥊⊢‿⌽⋈⌜views){F‿a 𝕊 𝕩:((-∘¬∘(»((0⊸=⊣)∧>)⊢)⌈⊢)⎉1)⌾(F a⊸⍉)𝕩}¨<𝕩}
+Exterior ← (⊢-○Exposed ¯1⊸=∘(Displace lib._fix)∘(-∘Interior+⊢))
+
+•Out "day18.1: "∾•Fmt Exposed cubes
+•Out "day18.2: "∾•Fmt Exterior cubes
diff --git a/users/sterni/exercises/aoc/lib.bqn b/users/sterni/exercises/aoc/lib.bqn
index 8554d1ee6..37c518d1f 100644
--- a/users/sterni/exercises/aoc/lib.bqn
+++ b/users/sterni/exercises/aoc/lib.bqn
@@ -13,3 +13,5 @@ SplitAt ← ((⊣≤↕∘≠∘⊢)⊔⊢)
 _fix ⇐ {𝕩 𝕊∘⊢⍟≢ 𝔽 𝕩}
 
 ImportBqnLibs ⇐ {•Import 𝕩∾˜"/"∾˜¯1↓1⊑•SH "printenv"‿"BQNLIBS"}
+
+Xor ⇐ (¬⊸∧∨∧⟜¬)