From af03b8491b48e7c22ebd817e4825cf33875051e3 Mon Sep 17 00:00:00 2001
From: Jeremy Kaplan <code@jdkaplan.dev>
Date: Mon, 8 Dec 2025 01:56:00 -0600
Subject: [PATCH] 2025 Day 1 Part 2

---
 2025/day01.ua | 39 ++++++++++++++++++++++++++++++++++-----
 1 file changed, 34 insertions(+), 5 deletions(-)

diff --git a/2025/day01.ua b/2025/day01.ua
index 69924af..be20f81 100644
--- a/2025/day01.ua
+++ b/2025/day01.ua
@@ -2,9 +2,38 @@
 
 Input ← Lines &fras "input/day01.txt"
 
-Dirs ← ≡°□ +⊃(¯=@L) (=@R) ⍚⊢ Input
-Amts ← ⋕⍚(↘ 1) Input
+Dirs ← ≡°□ +⊃(¯=@L) (=@R) ⍚⊢
+Amts ← ⋕⍚(↘ 1)
+Ops  ← × ⊃Dirs Amts
 
-× Dirs Amts
-⬚50\(◿ 100 +)
-/+ = 0
+Part₁ ← (
+  ⬚50\(◿100 +)
+  /+ =0
+)
+
+Div         ← ⌊⌵÷
+Rem         ← ×⊃(◿⊙⌵|±⋅)
+DivRem      ← ⊂ ⊃(Div|Rem)
+ChSgn       ← ≠∩±
+NeitherZero ← |2 =0 +∩(=0)
+CrossedZero ← |2 ×⊃(NeitherZero|ChSgn)
+TouchedZero ← |2 × ≠0 ⊙(=0)
+
+Update ← |2 Rem100 + Rem100      # op pos
+Z₁     ← |2 Div100 ⊙◌            # op [pos]
+Z₂     ← |2 Div100 +Rem100       # op pos
+Z₃     ← |2 TouchedZero ⟜+Rem100 # op pos
+Z₄     ← |2 CrossedZero ⟜+Rem100 # op pos
+
+Part₂ ← (
+  ⬚[0 50] /(|2
+    ⊃(⊡0|⊡1)
+    ⊙(⊂⊂⊂ ⊃(Z₁|Z₂|Z₃|Z₄|Update))
+    ˜∧+
+    ⊂
+  )
+  ⊢
+)
+
+Part₁ Ops Input
+Part₂ Ops Input