2025 11.1

Author: Lexicality

data

@@ -0,0 +1,68 @@
+// Copyright (c) 2025 Lexi Robinson
+//
+// Licensed under the EUPL, Version 1.2
+//
+// You may not use this work except in compliance with the Licence.
+// You should have received a copy of the Licence along with this work. If not, see:
+// <https://joinup.ec.europa.eu/collection/eupl/eupl-text-eupl-12>.
+// See the Licence for the specific language governing permissions and limitations under the Licence.
+
+use std::collections::HashMap;
+
+use cached::{UnboundCache, cached_key};
+use itertools::Itertools;
+
+use crate::AoCError;
+
+type Key = u32;
+type Store = HashMap<Key, Vec<Key>>;
+
+const fn to_id(input: &str) -> Key {
+    // all ids are 3 ascii letters, so 7 bits each.
+    let input = input.as_bytes();
+    let [a, b, c] = *input else {
+        panic!("Code must be 3 bytes")
+    };
+    ((a as u32) << 16) + ((b as u32) << 8) + (c as u32)
+}
+
+const START: Key = to_id("you");
+const END: Key = to_id("out");
+
+fn parse_line(input: String) -> crate::AoCResult<(Key, Vec<Key>)> {
+    let (gate, outputs) = input
+        .split_once(": ")
+        .ok_or_else(|| AoCError::new("Line {input} doesn't have a :"))?;
+
+    Ok((to_id(gate), outputs.split_whitespace().map(to_id).collect()))
+}
+
+cached_key! {
+    FIND_PATHS: UnboundCache<Key, usize> = UnboundCache::with_capacity(600);
+    Key = { id };
+    fn find_paths(id: Key, store: &Store) -> usize = {
+        let my_outputs = &store[&id];
+        log::debug!("Hello I'm {id} and my friends are {my_outputs:?}");
+        my_outputs
+            .iter()
+            .copied()
+            .map(|out_id| if out_id == END { 1 } else { find_paths(out_id, store)})
+            .sum::<usize>()
+    }
+}
+
+pub fn part_1(data: crate::DataIn) -> crate::AoCResult<String> {
+    let store: Store = data.map(parse_line).try_collect()?;
+    let ret = find_paths(START, &store);
+    Ok(ret.to_string())
+}
+
+inventory::submit!(crate::AoCDay {
+    year: "2025",
+    day: "11",
+    part_1: crate::AoCPart {
+        main: part_1,
+        example: part_1
+    },
+    part_2: None
+});

src/aoc/y2025/day11.rs

@@ -15,3 +15,4 @@ pub mod day06;
 pub mod day07;
 pub mod day08;
 pub mod day09;
+pub mod day11;