Add day13

day13/Cargo.lock

@@ -0,0 +1,54 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+version = 4
+
+[[package]]
+name = "aho-corasick"
+version = "1.1.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8e60d3430d3a69478ad0993f19238d2df97c507009a52b3c10addcd7f6bcb916"
+dependencies = [
+ "memchr",
+]
+
+[[package]]
+name = "day13"
+version = "0.1.0"
+dependencies = [
+ "regex",
+]
+
+[[package]]
+name = "memchr"
+version = "2.7.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "78ca9ab1a0babb1e7d5695e3530886289c18cf2f87ec19a575a0abdce112e3a3"
+
+[[package]]
+name = "regex"
+version = "1.11.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b544ef1b4eac5dc2db33ea63606ae9ffcfac26c1416a2806ae0bf5f56b201191"
+dependencies = [
+ "aho-corasick",
+ "memchr",
+ "regex-automata",
+ "regex-syntax",
+]
+
+[[package]]
+name = "regex-automata"
+version = "0.4.9"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "809e8dc61f6de73b46c85f4c96486310fe304c434cfa43669d7b40f711150908"
+dependencies = [
+ "aho-corasick",
+ "memchr",
+ "regex-syntax",
+]
+
+[[package]]
+name = "regex-syntax"
+version = "0.8.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "2b15c43186be67a4fd63bee50d0303afffcef381492ebe2c5d87f324e1b8815c"

day13/Cargo.toml

@@ -0,0 +1,7 @@
+[package]
+name = "day13"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
+regex = "1.11.1"

day13/src/main.rs

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+use regex::Regex;
+
+#[derive(Debug, Clone)]
+struct Machine {
+    x1: isize,
+    y1: isize,
+    x2: isize,
+    y2: isize,
+    x3: isize,
+    y3: isize,
+}
+
+#[rustfmt::skip]
+fn parse(input: &str) -> Vec<Machine> {
+    let re = Regex::new(r"\d+").unwrap();
+    input
+        .split("\n\n")
+        .map(|m| {
+            let mut captures = re.captures_iter(m);
+            Machine {
+                x1: captures.next().unwrap().get(0).unwrap().as_str().parse().unwrap(),
+                y1: captures.next().unwrap().get(0).unwrap().as_str().parse().unwrap(),
+                x2: captures.next().unwrap().get(0).unwrap().as_str().parse().unwrap(),
+                y2: captures.next().unwrap().get(0).unwrap().as_str().parse().unwrap(),
+                x3: captures.next().unwrap().get(0).unwrap().as_str().parse().unwrap(),
+                y3: captures.next().unwrap().get(0).unwrap().as_str().parse().unwrap(),
+            }
+        })
+        .collect()
+}
+
+fn solve(m: &Machine) -> isize {
+    let d = m.x1 * m.y2 - m.y1 * m.x2;
+    let a = (m.x3 * m.y2 - m.x2 * m.y3) / d;
+    let b = (m.x1 * m.y3 - m.x3 * m.y1) / d;
+    if a * m.x1 + b * m.x2 == m.x3 && a * m.y1 + b * m.y2 == m.y3 {
+        3 * a + b
+    } else {
+        0
+    }
+}
+
+fn part1(machines: &[Machine]) -> isize {
+    machines.iter().map(solve).sum()
+}
+
+fn part2(machines: &mut [Machine]) -> isize {
+    machines
+        .iter_mut()
+        .map(|m| {
+            m.x3 += 10000000000000;
+            m.y3 += 10000000000000;
+            m
+        })
+        .map(|m| solve(m))
+        .sum()
+}
+
+fn main() {
+    let mut input = parse(include_str!("../input.txt"));
+    println!("{}", part1(&input));
+    println!("{}", part2(&mut input));
+}