[2024] Day 25 initial solution

WOO LAST DAY

Author: connorslade

README.md

@@ -29,6 +29,7 @@ Thank you to [Eric Wastl](http://was.tl) for running this incredible yearly even
 - [Day 22: Monkey Market](aoc_2024/src/day_22.rs)
 - [Day 23: LAN Party](aoc_2024/src/day_23.rs)
 - [Day 24: Crossed Wires](aoc_2024/src/day_24.rs)
+- [Day 25: Code Chronicle](aoc_2024/src/day_25.rs)
 <!-- MARKER -->
 
 ## [2023](https://adventofcode.com/2023) [![aoc_2023](https://github.com/connorslade/advent-of-code/actions/workflows/aoc_2023.yml/badge.svg)](https://github.com/connorslade/advent-of-code/actions/workflows/aoc_2023.yml)

aoc_2024/src/day_25.rs

@@ -0,0 +1,135 @@
+use std::convert::identity;
+
+use aoc_lib::matrix::Grid;
+use common::{solution, Answer};
+use nd_vec::vector;
+
+solution!("Code Chronicle", 25);
+
+fn part_a(input: &str) -> Answer {
+    let mut keys = Vec::new();
+    let mut locks = Vec::new();
+
+    for item in input.split("\n\n") {
+        let (item, lock) = Key::parse(item);
+        if lock {
+            locks.push(item);
+        } else {
+            keys.push(item);
+        }
+    }
+
+    let mut out = 0;
+
+    for key in keys {
+        for lock in locks.iter() {
+            if key.fits(&lock) {
+                out += 1;
+            }
+        }
+    }
+
+    out.into()
+}
+
+fn part_b(input: &str) -> Answer {
+    Answer::Unimplemented
+}
+
+#[derive(Debug)]
+struct Key {
+    heights: [u8; 5],
+}
+
+impl Key {
+    fn parse(input: &str) -> (Self, bool) {
+        let grid = Grid::parse(input, identity);
+
+        let mut heights = [0; 5];
+        let mut is_lock = true;
+
+        for x in 0..5 {
+            let mut height = 0;
+            for y in 0..7 {
+                if y == 0 && grid[vector!(x, y)] != '#' {
+                    is_lock = false;
+                }
+
+                if grid[vector!(x, y)] == '#' {
+                    height += 1;
+                }
+            }
+
+            heights[x] = height - 1;
+        }
+
+        (Self { heights }, is_lock)
+    }
+
+    fn fits(&self, other: &Self) -> bool {
+        for (a, b) in self.heights.iter().zip(other.heights.iter()) {
+            if a + b > 5 {
+                return false;
+            }
+        }
+
+        true
+    }
+}
+
+#[cfg(test)]
+mod test {
+    use indoc::indoc;
+
+    const CASE: &str = indoc! {"
+        #####
+        .####
+        .####
+        .####
+        .#.#.
+        .#...
+        .....
+
+        #####
+        ##.##
+        .#.##
+        ...##
+        ...#.
+        ...#.
+        .....
+
+        .....
+        #....
+        #....
+        #...#
+        #.#.#
+        #.###
+        #####
+
+        .....
+        .....
+        #.#..
+        ###..
+        ###.#
+        ###.#
+        #####
+
+        .....
+        .....
+        .....
+        #....
+        #.#..
+        #.#.#
+        #####
+    "};
+
+    #[test]
+    fn part_a() {
+        assert_eq!(super::part_a(CASE), 3.into());
+    }
+
+    #[test]
+    fn part_b() {
+        assert_eq!(super::part_b(CASE), ().into());
+    }
+}

aoc_2024/src/lib.rs

@@ -24,6 +24,7 @@ mod day_21;
 mod day_22;
 mod day_23;
 mod day_24;
+mod day_25;
 // [import_marker]
 
 pub const SOLUTIONS: &[Solution] = &[
@@ -51,5 +52,6 @@ pub const SOLUTIONS: &[Solution] = &[
     day_22::SOLUTION,
     day_23::SOLUTION,
     day_24::SOLUTION,
+    day_25::SOLUTION,
     // [list_marker]
 ];