diff --git a/day13/Cargo.lock b/day13/Cargo.lock new file mode 100644 index 0000000..2707a29 --- /dev/null +++ b/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" diff --git a/day13/Cargo.toml b/day13/Cargo.toml new file mode 100644 index 0000000..7d375ce --- /dev/null +++ b/day13/Cargo.toml @@ -0,0 +1,7 @@ +[package] +name = "day13" +version = "0.1.0" +edition = "2021" + +[dependencies] +regex = "1.11.1" diff --git a/day13/src/main.rs b/day13/src/main.rs new file mode 100644 index 0000000..a438de3 --- /dev/null +++ b/day13/src/main.rs @@ -0,0 +1,63 @@ +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 { + 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)); +}