y2024d13 gonna be honest here, I was too lazy to do part2 by myself. I could have done it but it wold have taken some time as I have to remember how to solve linear equations

y2016/src/days/d8.rs

@@ -45,7 +45,7 @@ pub fn process_part1(input: &str, grid_size: (usize, usize)) -> i32 {
         .sum()
 }
 
-pub fn process_part2(input: &str) -> i32 {
+pub fn process_part2(_input: &str) -> i32 {
     0
 }
 

y2024/src/bin/d13.rs

@@ -0,0 +1,27 @@
+use std::{fs, time::Instant};
+
+use utils::time::get_elapsed_string;
+use y2024::days::d13;
+
+fn main() {
+    let now = Instant::now();
+    println!("Part 1:");
+    part1();
+    println!("Ran in {}", get_elapsed_string(now.elapsed()));
+    let now = Instant::now();
+    println!("Part 2:");
+    part2();
+    println!("Ran in {}", get_elapsed_string(now.elapsed()));
+}
+
+fn part1() {
+    let root = env!("CARGO_MANIFEST_DIR");
+    let content = fs::read_to_string(format!("{root}/resources/13_input.txt")).unwrap();
+    println!("{}", d13::process_part1(&content));
+}
+
+fn part2() {
+    let root = env!("CARGO_MANIFEST_DIR");
+    let content = fs::read_to_string(format!("{root}/resources/13_input.txt")).unwrap();
+    println!("{}", d13::process_part2(&content));
+}

y2024/src/days/d13.rs

@@ -0,0 +1,151 @@
+use core::panic;
+
+#[derive(Debug, Clone, Copy)]
+struct ClawMachine {
+    button_a: (i64, i64),
+    button_b: (i64, i64),
+    prize: (i64, i64),
+}
+
+impl ClawMachine {
+    fn parse(s: &str) -> Self {
+        let mut button_a = (0, 0);
+        let mut button_b = (0, 0);
+        let mut prize = (0, 0);
+        s.lines().for_each(|line| {
+            let (field, coords) = line.split_once(": ").unwrap();
+            if field == "Button A" {
+                let (x, y) = coords.split_once(", ").unwrap();
+                let x: i64 = x.split_once("+").unwrap().1.parse().unwrap();
+                let y: i64 = y.split_once("+").unwrap().1.parse().unwrap();
+                button_a = (x, y);
+            } else if field == "Button B" {
+                let (x, y) = coords.split_once(", ").unwrap();
+                let x: i64 = x.split_once("+").unwrap().1.parse().unwrap();
+                let y: i64 = y.split_once("+").unwrap().1.parse().unwrap();
+                button_b = (x, y);
+            } else if field == "Prize" {
+                let (x, y) = coords.split_once(", ").unwrap();
+                let x: i64 = x.split_once("=").unwrap().1.parse().unwrap();
+                let y: i64 = y.split_once("=").unwrap().1.parse().unwrap();
+                prize = (x, y);
+            } else {
+                panic!("Unknown machine information {line}");
+            }
+        });
+        Self {
+            button_a,
+            button_b,
+            prize,
+        }
+    }
+
+    fn correct(&mut self) {
+        self.prize.0 += 10000000000000;
+        self.prize.1 += 10000000000000;
+    }
+
+    fn parse_all(input: &str) -> Vec<Self> {
+        input.split("\n\n").map(Self::parse).collect()
+    }
+
+    //fn get_moves(&self) -> Option<(i64, i64)> {
+    //    if self.prize.0 % self.button_b.0 == 0
+    //        && self.prize.1 % self.button_b.1 == 0
+    //        && self.prize.0 / self.button_b.0 == self.prize.1 / self.button_b.1
+    //    {
+    //        let b_moves = self.prize.0 / self.button_b.0;
+    //        return Some((0, b_moves));
+    //    }
+
+    //    for b_presses in (1..=100).rev() {
+    //        let after_b_moves = (self.button_b.0 * b_presses, self.button_b.1 * b_presses);
+    //        if after_b_moves.0 < self.prize.0 && after_b_moves.1 < self.prize.1 {
+    //            for a_presses in 1..=100 {
+    //                let after_a_moves = (
+    //                    after_b_moves.0 + a_presses * self.button_a.0,
+    //                    after_b_moves.1 + a_presses * self.button_a.1,
+    //                );
+    //                if after_a_moves == self.prize {
+    //                    return Some((a_presses, b_presses));
+    //                }
+    //            }
+    //        }
+    //    }
+    //    None
+    //}
+}
+
+pub fn process_part1(input: &str) -> i64 {
+    let machines = ClawMachine::parse_all(input);
+    machines
+        .iter()
+        .map(|machine| {
+            let p = machine.prize;
+            let a = machine.button_a;
+            let b = machine.button_b;
+            let bm = (p.1 * a.0 - p.0 * a.1) / (b.1 * a.0 - b.0 * a.1);
+            let am = (p.0 - bm * b.0) / a.0;
+            if p.0 != am * a.0 + bm * b.0 || p.1 != am * a.1 + bm * b.1 {
+                0
+            } else {
+                am * 3 + bm
+            }
+        })
+        .sum()
+}
+
+pub fn process_part2(input: &str) -> i64 {
+    let mut machines = ClawMachine::parse_all(input);
+    for machine in machines.iter_mut() {
+        machine.correct();
+    }
+    machines
+        .iter()
+        .map(|machine| {
+            let p = machine.prize;
+            let a = machine.button_a;
+            let b = machine.button_b;
+            let bm = (p.1 * a.0 - p.0 * a.1) / (b.1 * a.0 - b.0 * a.1);
+            let am = (p.0 - bm * b.0) / a.0;
+            if p.0 != am * a.0 + bm * b.0 || p.1 != am * a.1 + bm * b.1 {
+                0
+            } else {
+                am * 3 + bm
+            }
+        })
+        .sum()
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    const INPUT: &str = "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";
+
+    #[test]
+    fn part1() {
+        let result = process_part1(INPUT);
+        assert_eq!(result, 480);
+    }
+
+    #[test]
+    fn part2() {
+        let result = process_part2(INPUT);
+        assert_eq!(result, 0);
+    }
+}

y2024/src/days/mod.rs

@@ -13,3 +13,5 @@ pub mod d10;
 pub mod d11;
 
 pub mod d12;
+
+pub mod d13;