feat: day 13

Cargo.lock

@@ -33,6 +33,7 @@ dependencies = [
  "color-eyre",
  "rayon",
  "regex",
+ "thiserror",
  "tracing",
  "tracing-subscriber",
  "tracing-test",
@@ -353,6 +354,26 @@ dependencies = [
  "unicode-ident",
 ]
 
+[[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 = "thread_local"
 version = "1.1.8"

Cargo.toml

@@ -17,6 +17,7 @@ full = [
     "day10",
     "day11",
     "day12",
+    "day13",
 ]
 default = ["full"]
 day1 = []
@@ -31,6 +32,7 @@ day9 = []
 day10 = []
 day11 = []
 day12 = []
+day13 = []
 
 
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
@@ -39,6 +41,7 @@ day12 = []
 color-eyre = "0.6.3"
 rayon = "1.10.0"
 regex = "1.11.1"
+thiserror = "2.0.6"
 tracing = "0.1.41"
 tracing-subscriber = "0.3.19"
 tracing-test = "0.2.5"

inputs/day13/example.txt

@@ -0,0 +1,15 @@
+Button A: X+94, Y+34
+Button B: X+22, Y+67
+Prize: X=8400, Y=5400
+
+Button A: X+26, Y+66
+Button B: X+67, Y+21
+Prize: X=12748, Y=12176
+
+Button A: X+17, Y+86
+Button B: X+84, Y+37
+Prize: X=7870, Y=6450
+
+Button A: X+69, Y+23
+Button B: X+27, Y+71
+Prize: X=18641, Y=10279

src/day13.rs

@@ -0,0 +1,186 @@
+#![allow(
+    clippy::cast_sign_loss,
+    clippy::cast_possible_wrap,
+    clippy::too_many_lines,
+    clippy::cast_possible_truncation,
+    clippy::cast_precision_loss,
+    clippy::float_cmp
+)]
+use std::str::FromStr;
+
+use color_eyre::eyre::{self, OptionExt};
+
+struct Elem {
+    x: usize,
+    y: usize,
+}
+struct Machine {
+    button_a: Elem,
+    button_b: Elem,
+    prize: Elem,
+}
+
+fn parse_button(s: &str) -> Result<Elem, eyre::Error> {
+    let positions = s.split_once(", ").ok_or_eyre("Button A line malformed")?;
+    Ok(Elem {
+        x: positions
+            .0
+            .split_once('+')
+            .ok_or_eyre("seems to be malformed")?
+            .1
+            .parse::<usize>()?,
+        y: positions
+            .1
+            .split_once('+')
+            .ok_or_eyre("seems to be malformed")?
+            .1
+            .parse::<usize>()?,
+    })
+}
+
+impl FromStr for Machine {
+    type Err = eyre::Error;
+    fn from_str(s: &str) -> Result<Self, Self::Err> {
+        let lines = s.lines().collect::<Vec<_>>();
+        let button_a = parse_button(lines.first().ok_or_eyre("Could not find button a line")?)?;
+        let button_b = parse_button(lines.get(1).ok_or_eyre("could not find button b line")?)?;
+        let prize_line = lines.get(2).ok_or_eyre("Could not find prize line")?;
+        let prizes = prize_line
+            .split_once(", ")
+            .ok_or_eyre("Could not parse prize line")?;
+        let prize = Elem {
+            x: prizes
+                .0
+                .split_once('=')
+                .ok_or_eyre("Could not parse prize")?
+                .1
+                .parse::<usize>()?,
+            y: prizes
+                .1
+                .split_once('=')
+                .ok_or_eyre("Could not parse prize")?
+                .1
+                .parse::<usize>()?,
+        };
+        Ok(Machine {
+            button_a,
+            button_b,
+            prize,
+        })
+    }
+}
+
+impl Machine {
+    pub fn play(&self) -> Option<usize> {
+        let machine = self;
+        let determinant = machine.button_a.x as f64 * machine.button_b.y as f64
+            - machine.button_a.y as f64 * machine.button_b.x as f64;
+        let a = ((-(machine.button_b.x as f64)) * (machine.prize.y as f64)
+            + machine.button_b.y as f64 * machine.prize.x as f64)
+            / determinant;
+        let b = (machine.button_a.x as f64 * machine.prize.y as f64
+            - machine.button_a.y as f64 * machine.prize.x as f64)
+            / determinant;
+        if a.floor() == a && b.floor() == b && a >= 0.0 && b >= 0.0 {
+            if a > 100.0 || b > 100.0 {
+                None
+            } else {
+                Some(a.round() as usize * 3 + b as usize)
+            }
+        } else {
+            None
+        }
+    }
+    pub fn play_without_limits(&self) -> Option<usize> {
+        let machine = self;
+        let determinant = machine.button_a.x as f64 * machine.button_b.y as f64
+            - machine.button_a.y as f64 * machine.button_b.x as f64;
+        let a = ((-(machine.button_b.x as f64)) * (machine.prize.y as f64)
+            + machine.button_b.y as f64 * machine.prize.x as f64)
+            / determinant;
+        let b = (machine.button_a.x as f64 * machine.prize.y as f64
+            - machine.button_a.y as f64 * machine.prize.x as f64)
+            / determinant;
+        if a.floor() == a && b.floor() == b && a >= 0.0 && b >= 0.0 {
+            Some(a.round() as usize * 3 + b as usize)
+        } else {
+            None
+        }
+    }
+}
+
+pub fn pt1(input: &str) -> usize {
+    input
+        .split("\n\n")
+        .flat_map(Machine::from_str)
+        .filter_map(|m| m.play())
+        .sum()
+}
+pub fn pt2(input: &str) -> usize {
+    input
+        .split("\n\n")
+        .flat_map(Machine::from_str)
+        .map(|mut m| {
+            m.prize.x += 10_000_000_000_000;
+            m.prize.y += 10_000_000_000_000;
+            m
+        })
+        .filter_map(|m| m.play_without_limits())
+        .sum()
+}
+
+#[cfg(test)]
+mod tests {
+    use tracing_test::traced_test;
+
+    use super::{pt1, pt2, Machine};
+    use std::fs::read_to_string;
+
+    #[traced_test]
+    #[test]
+    pub fn test_pt1() {
+        let input =
+            read_to_string("./inputs/day13/example.txt").expect("Missing example.txt for day13");
+        assert_eq!(pt1(&input), 480)
+    }
+    #[traced_test]
+    #[test]
+    pub fn test_machine_execution1() {
+        let m = Machine {
+            button_a: crate::day13::Elem { x: 94, y: 34 },
+            button_b: crate::day13::Elem { x: 22, y: 67 },
+            prize: crate::day13::Elem { x: 8400, y: 5400 },
+        };
+        assert_eq!(m.play(), Some(280))
+    }
+    #[traced_test]
+    #[test]
+    pub fn test_machine_execution2() {
+        let m = Machine {
+            button_a: crate::day13::Elem { x: 26, y: 66 },
+            button_b: crate::day13::Elem { x: 67, y: 21 },
+            prize: crate::day13::Elem { x: 12748, y: 12176 },
+        };
+        assert_eq!(m.play(), None)
+    }
+    #[traced_test]
+    #[test]
+    pub fn test_machine_execution3() {
+        let m = Machine {
+            button_a: crate::day13::Elem { x: 17, y: 86 },
+            button_b: crate::day13::Elem { x: 84, y: 37 },
+            prize: crate::day13::Elem { x: 7870, y: 6450 },
+        };
+        assert_eq!(m.play(), Some(200))
+    }
+    #[traced_test]
+    #[test]
+    pub fn test_machine_execution4() {
+        let m = Machine {
+            button_a: crate::day13::Elem { x: 69, y: 23 },
+            button_b: crate::day13::Elem { x: 27, y: 71 },
+            prize: crate::day13::Elem { x: 18641, y: 10279 },
+        };
+        assert_eq!(m.play(), None)
+    }
+}

src/main.rs

@@ -27,6 +27,8 @@ mod day10;
 mod day11;
 #[cfg(feature = "day12")]
 mod day12;
+#[cfg(feature = "day13")]
+mod day13;
 
 fn main() -> eyre::Result<()> {
     color_eyre::install()?;
@@ -57,6 +59,8 @@ fn main() -> eyre::Result<()> {
     solve_day(11, day11::pt1, day11::pt2);
     #[cfg(feature = "day12")]
     solve_day(12, day12::pt1, day12::pt2);
+    #[cfg(feature = "day13")]
+    solve_day(13, day13::pt1, day13::pt2);
     Ok(())
 }