Day 13

Cargo.lock

@@ -23,6 +23,8 @@ version = "0.1.0"
 dependencies = [
  "dotenvy",
  "itertools",
+ "pest",
+ "pest_derive",
  "rayon",
  "regex",
  "reqwest",
@@ -76,6 +78,15 @@ version = "2.6.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "b048fb63fd8b5923fc5aa7b340d8e156aec7ec02f0c78fa8a6ddc2613f6f71de"
 
+[[package]]
+name = "block-buffer"
+version = "0.10.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "3078c7629b62d3f0439517fa394996acacc5cbc91c5a20d8c658e77abd503a71"
+dependencies = [
+ "generic-array",
+]
+
 [[package]]
 name = "bumpalo"
 version = "3.16.0"
@@ -119,6 +130,15 @@ version = "0.8.7"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "773648b94d0e5d620f64f280777445740e61fe701025087ec8b57f45c791888b"
 
+[[package]]
+name = "cpufeatures"
+version = "0.2.16"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "16b80225097f2e5ae4e7179dd2266824648f3e2f49d9134d584b76389d31c4c3"
+dependencies = [
+ "libc",
+]
+
 [[package]]
 name = "crossbeam-deque"
 version = "0.8.5"
@@ -144,6 +164,26 @@ version = "0.8.20"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "22ec99545bb0ed0ea7bb9b8e1e9122ea386ff8a48c0922e43f36d45ab09e0e80"
 
+[[package]]
+name = "crypto-common"
+version = "0.1.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1bfb12502f3fc46cca1bb51ac28df9d618d813cdc3d2f25b9fe775a34af26bb3"
+dependencies = [
+ "generic-array",
+ "typenum",
+]
+
+[[package]]
+name = "digest"
+version = "0.10.7"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9ed9a281f7bc9b7576e61468ba615a66a5c8cfdff42420a70aa82701a3b1e292"
+dependencies = [
+ "block-buffer",
+ "crypto-common",
+]
+
 [[package]]
 name = "displaydoc"
 version = "0.2.5"
@@ -278,6 +318,16 @@ dependencies = [
  "slab",
 ]
 
+[[package]]
+name = "generic-array"
+version = "0.14.7"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "85649ca51fd72272d7821adaf274ad91c288277713d9c18820d8499a7ff69e9a"
+dependencies = [
+ "typenum",
+ "version_check",
+]
+
 [[package]]
 name = "getrandom"
 version = "0.2.15"
@@ -750,6 +800,51 @@ version = "2.3.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "e3148f5046208a5d56bcfc03053e3ca6334e51da8dfb19b6cdc8b306fae3283e"
 
+[[package]]
+name = "pest"
+version = "2.7.15"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8b7cafe60d6cf8e62e1b9b2ea516a089c008945bb5a275416789e7db0bc199dc"
+dependencies = [
+ "memchr",
+ "thiserror",
+ "ucd-trie",
+]
+
+[[package]]
+name = "pest_derive"
+version = "2.7.15"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "816518421cfc6887a0d62bf441b6ffb4536fcc926395a69e1a85852d4363f57e"
+dependencies = [
+ "pest",
+ "pest_generator",
+]
+
+[[package]]
+name = "pest_generator"
+version = "2.7.15"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7d1396fd3a870fc7838768d171b4616d5c91f6cc25e377b673d714567d99377b"
+dependencies = [
+ "pest",
+ "pest_meta",
+ "proc-macro2",
+ "quote",
+ "syn",
+]
+
+[[package]]
+name = "pest_meta"
+version = "2.7.15"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e1e58089ea25d717bfd31fb534e4f3afcc2cc569c70de3e239778991ea3b7dea"
+dependencies = [
+ "once_cell",
+ "pest",
+ "sha2",
+]
+
 [[package]]
 name = "pin-project-lite"
 version = "0.2.15"
@@ -1034,6 +1129,17 @@ dependencies = [
  "serde",
 ]
 
+[[package]]
+name = "sha2"
+version = "0.10.8"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "793db75ad2bcafc3ffa7c68b215fee268f537982cd901d132f89c6343f3a3dc8"
+dependencies = [
+ "cfg-if",
+ "cpufeatures",
+ "digest",
+]
+
 [[package]]
 name = "shlex"
 version = "1.3.0"
@@ -1148,6 +1254,26 @@ dependencies = [
  "windows-sys 0.59.0",
 ]
 
+[[package]]
+name = "thiserror"
+version = "2.0.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8fec2a1820ebd077e2b90c4df007bebf344cd394098a13c563957d0afc83ea47"
+dependencies = [
+ "thiserror-impl",
+]
+
+[[package]]
+name = "thiserror-impl"
+version = "2.0.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d65750cab40f4ff1929fb1ba509e9914eb756131cef4210da8d5d700d26f6312"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn",
+]
+
 [[package]]
 name = "tinystr"
 version = "0.7.6"
@@ -1238,6 +1364,18 @@ version = "0.2.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "e421abadd41a4225275504ea4d6566923418b7f05506fbc9c0fe86ba7396114b"
 
+[[package]]
+name = "typenum"
+version = "1.17.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "42ff0bf0c66b8238c6f3b578df37d0b7848e55df8577b3f74f92a69acceeb825"
+
+[[package]]
+name = "ucd-trie"
+version = "0.1.7"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "2896d95c02a80c6d6a5d6e953d479f5ddf2dfdb6a244441010e373ac0fb88971"
+
 [[package]]
 name = "unicode-ident"
 version = "1.0.14"
@@ -1279,6 +1417,12 @@ version = "0.2.15"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "accd4ea62f7bb7a82fe23066fb0957d48ef677f6eeb8215f372f52e48bb32426"
 
+[[package]]
+name = "version_check"
+version = "0.9.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "0b928f33d975fc6ad9f86c8f283853ad26bdd5b10b7f1542aa2fa15e2289105a"
+
 [[package]]
 name = "want"
 version = "0.3.1"

Cargo.toml

@@ -6,6 +6,8 @@ edition = "2021"
 [dependencies]
 dotenvy = "0.15.7"
 itertools = "0.13.0"
+pest = "2.7.15"
+pest_derive = "2.7.15"
 rayon = "1.10.0"
 regex = "1.11.1"
 reqwest = { version = "0.12.9", features = ["blocking"] }

src/day13.rs

@@ -0,0 +1,95 @@
+use itertools::Itertools;
+use pest::{
+    iterators::{Pair, Pairs},
+    Parser,
+};
+
+const OFFSETS: (u64, u64) = (10000000000000, 10000000000000);
+
+pub fn day13() {
+    let cost: f64 = parse_machines(&crate::input(13))
+        .iter()
+        .filter_map(|machine| {
+            let (c, d) = machine.prize;
+            let (a, b) = &machine.buttons;
+
+            let bn = (d - c * a.y / a.x) / (b.y - b.x * a.y / a.x);
+            let an = (c - bn * b.x) / a.x;
+
+            // Both solutions must be whole numbers
+            let winnable = [an, bn]
+                .iter()
+                .all(|&n| n >= -0.01 && (n.round() - n).abs() <= 0.01);
+            if winnable {
+                Some(an.round() * a.cost + bn.round() * b.cost)
+            } else {
+                None
+            }
+        })
+        .sum();
+    println!("Minimum Cost: {:?}", cost);
+}
+
+struct Machine {
+    buttons: (Button, Button),
+    prize: (f64, f64),
+}
+
+struct Button {
+    cost: f64,
+    x: f64,
+    y: f64,
+}
+
+#[derive(pest_derive::Parser)]
+#[grammar = "grammars/day13.pest"]
+struct MachinesParser {}
+
+fn parse_machines(input: &str) -> Vec<Machine> {
+    MachinesParser::parse(Rule::machines, input)
+        .unwrap()
+        .nth(0)
+        .unwrap()
+        .into_inner()
+        .map(Pair::<'_, Rule>::into_inner)
+        .map(Machine::parse)
+        .collect()
+}
+
+impl Machine {
+    fn parse(input: Pairs<'_, Rule>) -> Self {
+        let (a, b, prize) = input.map(|p| p.into_inner()).collect_tuple().unwrap();
+
+        let buttons = [a, b]
+            .into_iter()
+            .map(Button::parse)
+            .collect_tuple()
+            .unwrap();
+
+        let prize = prize
+            .map(|n| n.as_str().parse::<u64>().unwrap())
+            .collect_tuple()
+            .map(|(x, y)| ((x + OFFSETS.0) as f64, (y + OFFSETS.1) as f64))
+            .unwrap();
+
+        Self { buttons, prize }
+    }
+}
+
+impl Button {
+    fn parse(input: Pairs<'_, Rule>) -> Self {
+        let (t, x, y) = input.collect_tuple().unwrap();
+
+        let cost = match t.as_str() {
+            "A" => 3.,
+            "B" => 1.,
+            _ => unreachable!(),
+        };
+
+        Self {
+            x: x.as_str().parse::<f64>().unwrap(),
+            y: y.as_str().parse::<f64>().unwrap(),
+            cost,
+        }
+    }
+}

src/grammars/day13.pest

@@ -0,0 +1,11 @@
+_WHITESPACE = _{ " " }
+newline = _{ "\n" }
+
+number = { ASCII_DIGIT+ }
+button_type = { "A" | "B" }
+button = { "Button " ~ button_type ~ ": X+" ~ number ~ ", Y+" ~ number ~ newline }
+prize = { "Prize: X=" ~ number ~ ", Y=" ~ number ~ newline }
+machine = { button ~ button ~ prize ~ newline? }
+
+eoi = _{ !ANY }
+machines = { SOI ~ machine+ ~ eoi }

src/main.rs

@@ -22,10 +22,12 @@ mod day9;
 mod day10;
 #[allow(dead_code)]
 mod day11;
+#[allow(dead_code)]
 mod day12;
+mod day13;
 
 fn main() {
-    day12::day12();
+    day13::day13();
 }
 
 pub fn input(day: u8) -> String {