feat(sterni/aoc/2022): day10 BQN solution r/5403

I cheated a bit to skip implementing multi cycle instructions. The VM is
pretty much a normal tail recursive function, but working with scalars
in BQN is on brand-ish. Array programming helps again when drawing the
picture on screen.

Change-Id: I2562c862e228f633c5fad09e503529c6e0785112
Reviewed-on: https://cl.tvl.fyi/c/depot/+/7556
Tested-by: BuildkiteCI
Reviewed-by: sterni <sternenseemann@systemli.org>
Autosubmit: sterni <sternenseemann@systemli.org>

2 files changed, 30 insertions, 1 deletions

diff --git a/users/sterni/exercises/aoc/2022/10/10.bqn b/users/sterni/exercises/aoc/2022/10/10.bqn
new file mode 100644
index 000000000000..59cfa0e8d3c8
--- /dev/null
+++ b/users/sterni/exercises/aoc/2022/10/10.bqn
@@ -0,0 +1,25 @@
+⟨SplitOn,ReadDec⟩ ← •Import "../../lib.bqn"
+# Instead of implementing the VM described in the problem, translate the
+# program to instructions with equivalent timing for a similar VM that
+# only needs 1 cycle for every instruction.
+is ← ∾{"noop": <"noop"; 𝕩: (<"noop")∾<ReadDec⌾(1⊸⊑) (<' ') SplitOn 𝕩}¨ •FLines "input"
+
+Op ← {x 𝕊 "noop": x;x 𝕊 "addx"‿i: x+i}
+Draw ← {𝕊 c‿x‿pic: pic∨(↕240)((c-1)⊸=∘⊣∧∊)(⌊⌾(÷⟜40)c)+¯1+x+↕3}
+_vm ← {
+  is _self s: (⊑s)≥≠is? s;
+  is _self prev‿sum‿x‿pic:
+  cycle ← prev+1
+  is _self ⟨
+    cycle,
+    sum+x×cycle×⊑cycle∊20‿60‿100‿140‿180‿220,
+    x Op (¯1+cycle)⊑is,
+    Draw cycle‿x‿pic
+  ⟩
+}
+
+·‿sum‿·‿pic ← is _vm 1‿0‿1‿(240⥊0)
+
+•Out "day10.1: "∾•Fmt sum
+•Out "day10.2:"
+•Show (⊑⟜".#")¨ ∘‿40⥊pic
diff --git a/users/sterni/exercises/aoc/lib.bqn b/users/sterni/exercises/aoc/lib.bqn
index 636eeace78d2..172343b41979 100644
--- a/users/sterni/exercises/aoc/lib.bqn
+++ b/users/sterni/exercises/aoc/lib.bqn
@@ -1,6 +1,10 @@
 IsAsciiNum ⇐ ('0'⊸≤∧≤⟜'9')
 
-ReadInt ⇐ {(𝕨⊸×+⊣)´∘⌽-⟜'0'𝕩} # stolen from leah2
+# based on leah2's function
+ReadInt ⇐ {
+  𝕨 𝕊 𝕩: '-'=⊑𝕩? -𝕨 𝕊 1↓𝕩;
+  𝕨 𝕊 𝕩: (𝕨⊸×+⊣)´∘⌽-⟜'0'𝕩
+}
 ReadDec ⇐ 10⊸ReadInt
 
 SplitOn ⇐ ((⊢ (-1˙)⍟⊣¨ +`∘(1⊸»<⊢))∘(≡¨)⊔⊢)