11

Author: Tom-Willemsen

aoc2025_wasm/inputs

@@ -0,0 +1,93 @@
+use anyhow::{Context, Result};
+use std::collections::HashMap;
+
+fn connections_from_line(inp: &str) -> Result<Vec<(&str, &str)>> {
+    let (here, there) = inp.split_once(": ").context("bad format")?;
+
+    Ok(there
+        .split(" ")
+        .flat_map(|x| [(here, x)])
+        .collect::<Vec<_>>())
+}
+
+fn pathfind(connections: &[(&str, &str)], start: &str, end: &str) -> u64 {
+    let mut map = HashMap::<&str, u64>::default();
+    map.insert(start, 1);
+
+    let mut ans = 0;
+
+    for _ in 0..connections.len() {
+        let mut new = HashMap::<&str, u64>::default();
+
+        connections.iter().for_each(|(s, e)| {
+            if let Some(oldval) = map.get(s) {
+                *new.entry(e).or_insert(0) += oldval;
+            }
+        });
+
+        ans += *new.get(end).unwrap_or(&0);
+
+        std::mem::swap(&mut new, &mut map);
+    }
+
+    ans
+}
+
+fn parse(inp: &str) -> Result<Vec<(&str, &str)>> {
+    let connections = inp
+        .trim()
+        .lines()
+        .map(connections_from_line)
+        .collect::<Result<Vec<_>>>()?;
+
+    Ok(connections.into_iter().flatten().collect::<Vec<_>>())
+}
+
+fn calculate_p1(connections: &[(&str, &str)]) -> u64 {
+    pathfind(connections, "you", "out")
+}
+
+fn calculate_p2(connections: &[(&str, &str)]) -> u64 {
+    (pathfind(connections, "svr", "dac")
+        * pathfind(connections, "dac", "fft")
+        * pathfind(connections, "fft", "out"))
+        + (pathfind(connections, "svr", "fft")
+            * pathfind(connections, "fft", "dac")
+            * pathfind(connections, "dac", "out"))
+}
+
+pub fn run_2025_11(inp: &str) -> Result<String> {
+    let connections = parse(inp)?;
+    let p1 = calculate_p1(&connections);
+    let p2 = calculate_p2(&connections);
+    Ok(format!("{p1}\n{p2}"))
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    const EXAMPLE_DATA: &str = include_str!("../inputs/examples/2025_11");
+    const EXAMPLE_DATA_P2: &str = include_str!("../inputs/examples/2025_11_2");
+    const REAL_DATA: &str = include_str!("../inputs/real/2025_11");
+
+    #[test]
+    fn test_example_p1() {
+        assert_eq!(calculate_p1(&parse(EXAMPLE_DATA).unwrap()), 5);
+    }
+
+    #[test]
+    fn test_example_p2() {
+        assert_eq!(calculate_p2(&parse(EXAMPLE_DATA_P2).unwrap()), 2);
+    }
+
+    #[test]
+    fn test_real_p1() {
+        assert_eq!(calculate_p1(&parse(REAL_DATA).unwrap()), 428);
+    }
+
+    #[test]
+    fn test_real_p2() {
+        assert_eq!(calculate_p2(&parse(REAL_DATA).unwrap()), 331468292364745);
+    }
+}

aoc2025_wasm/src/impl_2025_11.rs

@@ -9,6 +9,7 @@ mod impl_2025_07;
 mod impl_2025_08;
 mod impl_2025_09;
 mod impl_2025_10;
+mod impl_2025_11;
 pub(crate) mod union_find;
 
 pub use wasm_bindgen_rayon::init_thread_pool;
@@ -29,6 +30,7 @@ pub fn run_day(day: u32, input: &str) -> String {
         8 => impl_2025_08::run_2025_08(input),
         9 => impl_2025_09::run_2025_09(input),
         10 => impl_2025_10::run_2025_10(input),
+        11 => impl_2025_11::run_2025_11(input),
         _ => Err(anyhow!("No solution for that day yet")),
     };