From cd30cd98fa1a13fb2573550e54b352462ccf87df Mon Sep 17 00:00:00 2001
From: Joe Hildebrand <joe-github@cursive.net>
Date: Sat, 7 Dec 2024 22:38:53 -0700
Subject: [PATCH] Day 8

---
 day8.peggy   |  1 +
 day8.ts      | 87 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 inputs       |  2 +-
 t            |  9 ------
 test/day8.js |  1 +
 5 files changed, 90 insertions(+), 10 deletions(-)
 create mode 100644 day8.peggy
 create mode 100644 day8.ts
 delete mode 100644 t
 create mode 100644 test/day8.js

diff --git a/day8.peggy b/day8.peggy
new file mode 100644
index 0000000..cdcfc7c
--- /dev/null
+++ b/day8.peggy
@@ -0,0 +1 @@
+lines = (@[^\n]+ "\n")*
diff --git a/day8.ts b/day8.ts
new file mode 100644
index 0000000..c7fa79d
--- /dev/null
+++ b/day8.ts
@@ -0,0 +1,87 @@
+import { Point, Rect } from './lib/rect.ts';
+import { Sequence } from './lib/sequence.ts';
+import { type MainArgs, parseFile } from './lib/utils.ts';
+
+type Parsed = string[][];
+
+class Field extends Rect {
+  antennae = new Map<string, Point[]>();
+  nodes: Point[] = [];
+
+  constructor(inp: Parsed, self = false) {
+    super(inp);
+    this.forEach((v, x, y) => {
+      if (v === '.') {
+        return;
+      }
+      let m = this.antennae.get(v);
+      if (!m) {
+        m = [];
+        this.antennae.set(v, m);
+      }
+      const p = new Point(x, y);
+      m.push(p);
+      if (self) {
+        this.nodes.push(p);
+      }
+    });
+  }
+
+  push(p: Point): boolean {
+    if (!this.check(p)) {
+      return false;
+    }
+    this.nodes.push(p);
+    return true;
+  }
+
+  count(): number {
+    const locs = new Set<string>();
+    for (const p of this.nodes) {
+      if (this.check(p)) {
+        locs.add(p.toString());
+      }
+    }
+    return locs.size;
+  }
+}
+
+function part1(inp: Parsed): number {
+  const r = new Field(inp);
+
+  for (const [_k, v] of r.antennae) {
+    for (const [a, b] of new Sequence(v).combinations(2)) {
+      const dx = a.x - b.x;
+      const dy = a.y - b.y;
+      r.push(a.xlate(dx, dy));
+      r.push(b.xlate(-dx, -dy));
+    }
+  }
+
+  return r.count();
+}
+
+function part2(inp: Parsed): number {
+  const r = new Field(inp, true);
+
+  for (const [_k, v] of r.antennae) {
+    for (const [a, b] of new Sequence(v).combinations(2)) {
+      const dx = a.x - b.x;
+      const dy = a.y - b.y;
+      let p = a.xlate(dx, dy);
+      while (r.push(p)) {
+        p = p.xlate(dx, dy);
+      }
+      p = b.xlate(-dx, -dy);
+      while (r.push(p)) {
+        p = p.xlate(-dx, -dy);
+      }
+    }
+  }
+  return r.count();
+}
+
+export default async function main(args: MainArgs): Promise<[number, number]> {
+  const inp = await parseFile<Parsed>(args);
+  return [part1(inp), part2(inp)];
+}
diff --git a/inputs b/inputs
index 977e7c4..7f179a5 160000
--- a/inputs
+++ b/inputs
@@ -1 +1 @@
-Subproject commit 977e7c4946d3690df71d455017d993575d975aa8
+Subproject commit 7f179a501ebc3cba464c14c60f099ce151cf0089
diff --git a/t b/t
deleted file mode 100644
index fc6e099..0000000
--- a/t
+++ /dev/null
@@ -1,9 +0,0 @@
-190: 10 19
-3267: 81 40 27
-83: 17 5
-156: 15 6
-7290: 6 8 6 15
-161011: 16 10 13
-192: 17 8 14
-21037: 9 7 18 13
-292: 11 6 16 20
diff --git a/test/day8.js b/test/day8.js
new file mode 100644
index 0000000..d5f003b
--- /dev/null
+++ b/test/day8.js
@@ -0,0 +1 @@
+export default [240, 955];