Merge branch 'main' of ssh://git.flueren.eu:2202/JonOfUs/advent-of-code-2024

res/11/example

@@ -0,0 +1 @@
+125 17

res/11/input

@@ -0,0 +1 @@
+814 1183689 0 1 766231 4091 93836 46

res/13/example

@@ -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/days/d11.rs

@@ -1,4 +1,4 @@
-use std::fs;
+use std::{collections::HashMap, fs};
 
 pub fn solve() {
     let path = "res/11/input";
@@ -6,11 +6,58 @@ pub fn solve() {
     #[allow(unused)]
     let contents = fs::read_to_string(path).expect("Something went wrong reading the file");
 
-    let result: usize = 0;
+    let mut map: HashMap<usize, usize> = HashMap::new();
+    contents
+        .trim()
+        .split(' ')
+        .map(|n| n.parse::<usize>().unwrap())
+        .for_each(|n| {
+            map.insert(n, 1);
+        });
+
+    for _ in 0..25 {
+        map = blink(map);
+    }
+
+    let result: usize = map.iter().map(|(_, v)| v).sum();
 
     println!("Result 1: {}", result);
 
-    let result: usize = 0;
+    for _ in 0..50 {
+        map = blink(map);
+    }
+
+    let result: usize = map.iter().map(|(_, v)| v).sum();
 
     println!("Result 2: {}", result);
 }
+
+fn blink(map: HashMap<usize, usize>) -> HashMap<usize, usize> {
+    let mut new_map: HashMap<usize, usize> = HashMap::new();
+    for (k, v) in map.iter() {
+        if *k == 0 {
+            *new_map.entry(1).or_insert(0) += *v;
+        } else if k.to_string().len() % 2 == 0 {
+            // split num into two halves
+            let n1 = k
+                .to_string()
+                .chars()
+                .take(k.to_string().len() / 2)
+                .collect::<String>()
+                .parse::<usize>()
+                .unwrap();
+            let n2 = k
+                .to_string()
+                .chars()
+                .skip(k.to_string().len() / 2)
+                .collect::<String>()
+                .parse::<usize>()
+                .unwrap();
+            *new_map.entry(n1).or_insert(0) += *v;
+            *new_map.entry(n2).or_insert(0) += *v;
+        } else {
+            *new_map.entry((*k) * 2024).or_insert(0) += *v;
+        }
+    }
+    new_map
+}

src/days/d13.rs

@@ -1,16 +1,79 @@
 use std::fs;
 
+use scan_fmt::scan_fmt;
+
 pub fn solve() {
     let path = "res/13/input";
 
     #[allow(unused)]
     let contents = fs::read_to_string(path).expect("Something went wrong reading the file");
 
-    let result: usize = 0;
+    let machines: Vec<((isize, isize), (isize, isize), (isize, isize))> = contents
+        .split("\n\n")
+        .map(|block| {
+            let (x1, y1, x2, y2, xt, yt) = scan_fmt!(
+                block,
+                "Button A: X+{}, Y+{}\nButton B: X+{}, Y+{}\nPrize: X={}, Y={}",
+                isize,
+                isize,
+                isize,
+                isize,
+                isize,
+                isize
+            )
+            .unwrap();
+            ((x1, y1), (x2, y2), (xt, yt))
+        })
+        .collect();
+
+    let result: isize = machines
+        .iter()
+        .map(|m| {
+            let ((ax, ay), (bx, by), (xt, yt)) = *m;
+            let (mut a, mut b) = (0, 0);
+            while b * bx < xt && b * by < yt {
+                b += 1;
+            }
+            while (b * bx + a * ax != xt || b * by + a * ay != yt) && b > 0 {
+                b -= 1;
+                while b * bx + a * ax < xt && b * by + a * ay < yt {
+                    a += 1;
+                }
+            }
+
+            if b * bx + a * ax == xt && b * by + a * ay == yt {
+                return b + a * 3;
+            }
+
+            return 0;
+        })
+        .sum();
 
     println!("Result 1: {}", result);
 
-    let result: usize = 0;
+    let result: isize = machines
+        .iter()
+        .map(|m| {
+            let ((ax, ay), (bx, by), (xt, yt)) = *m;
+            let xt = xt + 10000000000000;
+            let yt = yt + 10000000000000;
+
+            let b_left = by * ax - bx * ay;
+            let b_right = yt * ax - xt * ay;
+            let b = b_right / b_left;
+            if b_left * b != b_right || b < 0 {
+                return 0;
+            }
+
+            let a_left = ax;
+            let a_right = xt - b * bx;
+            let a = a_right / a_left;
+            if a_left * a != a_right || a < 0 {
+                return 0;
+            }
+            a * 3 + b
+        })
+        .sum();
 
     println!("Result 2: {}", result);
 }