Year 2025 Day 10

Author: maneatingape

README.md

@@ -86,6 +86,7 @@ Performance is reasonable even on older hardware, for example a 2011 MacBook Pro
 | 7 | [Laboratories](https://adventofcode.com/2025/day/7) | [Source](src/year2025/day07.rs) | 5 |
 | 8 | [Playground](https://adventofcode.com/2025/day/8) | [Source](src/year2025/day08.rs) | 527 |
 | 9 | [Movie Theater](https://adventofcode.com/2025/day/9) | [Source](src/year2025/day09.rs) | 668 |
+| 10 | [Factory](https://adventofcode.com/2025/day/10) | [Source](src/year2025/day10.rs) | 126* |
 
 ## 2024
 

benches/benchmark.rs

@@ -95,5 +95,5 @@ benchmark!(year2024
 );
 
 benchmark!(year2025
-    day01, day02, day03, day04, day05, day06, day07, day08, day09
+    day01, day02, day03, day04, day05, day06, day07, day08, day09, day10
 );

src/lib.rs

@@ -74,5 +74,5 @@ library!(year2024 "Locate the Chief Historian in time for the big Christmas slei
 );
 
 library!(year2025 "Finish the North Pole decorations in time for Christmas."
-    day01, day02, day03, day04, day05, day06, day07, day08, day09
+    day01, day02, day03, day04, day05, day06, day07, day08, day09, day10
 );

src/main.rs

@@ -141,5 +141,5 @@ run!(year2024
 );
 
 run!(year2025
-    day01, day02, day03, day04, day05, day06, day07, day08, day09
+    day01, day02, day03, day04, day05, day06, day07, day08, day09, day10
 );

src/year2025/day10.rs

@@ -0,0 +1,62 @@
+//! # Factory
+use crate::util::bitset::*;
+use crate::util::parse::*;
+
+type Machine = (u64, Vec<u64>, Vec<u64>);
+
+pub fn parse(input: &str) -> Vec<Machine> {
+    input
+        .lines()
+        .map(|line| {
+            let tokens: Vec<_> = line.split_ascii_whitespace().collect();
+            let first = tokens[0].as_bytes();
+            let last = tokens.len() - 1;
+
+            let lights = first[1..first.len() - 1]
+                .iter()
+                .rev()
+                .fold(0, |acc, &b| (acc << 1) | u64::from(b == b'#'));
+            let buttons = tokens[1..last]
+                .iter()
+                .map(|token| token.iter_unsigned::<u64>().fold(0, |acc, i| acc | (1 << i)))
+                .collect();
+            let joltages = tokens[last].iter_unsigned::<u64>().collect();
+
+            (lights, buttons, joltages)
+        })
+        .collect()
+}
+
+pub fn part1(input: &[Machine]) -> u32 {
+    input
+        .iter()
+        .map(|(lights, buttons, _)| {
+            let limit = 1 << buttons.len();
+            let mut set = 0;
+
+            loop {
+                set += 1;
+                let mut n = (1 << set) - 1;
+
+                while n < limit {
+                    if *lights == n.biterator().fold(0, |acc, i| acc ^ buttons[i]) {
+                        return set;
+                    }
+                    n = next_same_bits(n);
+                }
+            }
+        })
+        .sum()
+}
+
+pub fn part2(_input: &[Machine]) -> u32 {
+    123456789
+}
+
+fn next_same_bits(n: i32) -> i32 {
+    let smallest = n & -n;
+    let ripple = n + smallest;
+    let ones = n ^ ripple;
+    let next = (ones >> 2) / smallest;
+    ripple | next
+}

tests/test.rs

@@ -87,5 +87,5 @@ test!(year2024
 );
 
 test!(year2025
-    day01, day02, day03, day04, day05, day06, day07, day08, day09
+    day01, day02, day03, day04, day05, day06, day07, day08, day09, day10
 );

tests/year2025/day10.rs

@@ -0,0 +1,17 @@
+use aoc::year2025::day10::*;
+
+const EXAMPLE: &str = "\
+[.##.] (3) (1,3) (2) (2,3) (0,2) (0,1) {3,5,4,7}
+[...#.] (0,2,3,4) (2,3) (0,4) (0,1,2) (1,2,3,4) {7,5,12,7,2}
+[.###.#] (0,1,2,3,4) (0,3,4) (0,1,2,4,5) (1,2) {10,11,11,5,10,5}";
+
+#[test]
+fn part1_test() {
+    let input = parse(EXAMPLE);
+    assert_eq!(part1(&input), 7);
+}
+
+#[test]
+fn part2_test() {
+    // No working part two yet.
+}