Cargo.lock

@@ -20,10 +20,6 @@ dependencies = [
  "winnow",
 ]
 
-[[package]]
-name = "day04"
-version = "0.1.0"
-
 [[package]]
 name = "memchr"
 version = "2.7.4"

Cargo.toml

@@ -1,6 +1,6 @@
 [workspace]
 resolver = "2"
-members = ["day01", "day02", "day03", "day04"]
+members = ["day01", "day02", "day03"]
 
 [workspace.dependencies]
 winnow = "0.6"

day04/Cargo.toml

@@ -1,7 +0,0 @@
-[package]
-name = "day04"
-version = "0.1.0"
-edition = "2024"
-
-[dependencies]
-

day04/src/main.rs

@@ -1,173 +0,0 @@
-#![feature(let_chains)]
-
-static MAS: [char; 3] = ['M', 'A', 'S'];
-static DIRS: [Dir; 8] = [
-    Dir::N,
-    Dir::S,
-    Dir::E,
-    Dir::W,
-    Dir::NE,
-    Dir::NW,
-    Dir::SE,
-    Dir::SW,
-];
-
-fn main() {
-    let input = std::fs::read_to_string("input").unwrap();
-    println!("{}", pt1(&input));
-    println!("{}", pt2(&input));
-}
-
-fn pt1(input: &str) -> u32 {
-    let mut total = 0;
-    let board = Board::new(input);
-
-    for (r, row) in board.rows.iter().enumerate() {
-        for (c, letter) in row.iter().enumerate() {
-            if letter == &'X' {
-                for &dir in DIRS.iter() {
-                    if find_xmas(&board, (r, c), dir) {
-                        total += 1;
-                    }
-                }
-            }
-        }
-    }
-
-    total
-}
-
-fn find_xmas(board: &Board, loc: (usize, usize), dir: Dir) -> bool {
-    let (mut r, mut c) = loc;
-    for l in MAS {
-        if let Some(&nl) = board.next((r, c), dir) {
-            if nl != l {
-                return false;
-            }
-            (r, c) = dir.next((r, c));
-        } else {
-            return false;
-        }
-    }
-    true
-}
-
-fn pt2(input: &str) -> u32 {
-    let mut total = 0;
-    let board = Board::new(input);
-
-    for (r, row) in board.rows.iter().enumerate() {
-        for (c, letter) in row.iter().enumerate() {
-            if letter == &'A' {
-                if find_x_mas(&board, (r, c)) {
-                    total += 1;
-                }
-            }
-        }
-    }
-
-    total
-}
-
-fn find_x_mas(board: &Board, loc: (usize, usize)) -> bool {
-    let one = if let Some(&nw) = (board.next(loc, Dir::NW))
-        && let Some(&se) = board.next(loc, Dir::SE)
-    {
-        if (nw == 'M' && se == 'S') || (nw == 'S' && se == 'M') {
-            true
-        } else {
-            false
-        }
-    } else {
-        false
-    };
-    let two = if let Some(&ne) = (board.next(loc, Dir::NE))
-        && let Some(&sw) = board.next(loc, Dir::SW)
-    {
-        if (ne == 'M' && sw == 'S') || (ne == 'S' && sw == 'M') {
-            true
-        } else {
-            false
-        }
-    } else {
-        false
-    };
-
-    one && two
-}
-
-struct Board {
-    rows: Vec<Vec<char>>,
-}
-
-impl Board {
-    fn new(input: &str) -> Self {
-        let rows = input.split('\n').map(|l| l.chars().collect()).collect();
-        Board { rows }
-    }
-
-    fn at(&self, loc: (usize, usize)) -> Option<&char> {
-        self.rows.get(loc.0).and_then(|r| r.get(loc.1))
-    }
-
-    fn next(&self, loc: (usize, usize), dir: Dir) -> Option<&char> {
-        let (nr, nc) = dir.next(loc);
-        self.at((nr, nc))
-    }
-}
-
-#[derive(Debug, PartialEq, Eq, Clone, Copy)]
-enum Dir {
-    N,
-    S,
-    E,
-    W,
-    NE,
-    NW,
-    SE,
-    SW,
-}
-
-impl Dir {
-    fn next(&self, loc: (usize, usize)) -> (usize, usize) {
-        let (r, c) = loc;
-        let (nr, nc) = match self {
-            Dir::N => (r.wrapping_sub(1), c),
-            Dir::S => (r + 1, c),
-            Dir::E => (r, c + 1),
-            Dir::W => (r, c.wrapping_sub(1)),
-            Dir::NE => (r.wrapping_sub(1), c + 1),
-            Dir::NW => (r.wrapping_sub(1), c.wrapping_sub(1)),
-            Dir::SE => (r + 1, c + 1),
-            Dir::SW => (r + 1, c.wrapping_sub(1)),
-        };
-
-        (nr, nc)
-    }
-}
-
-#[cfg(test)]
-mod test {
-    use super::*;
-
-    static INPUT: &str = "MMMSXXMASM
-MSAMXMSMSA
-AMXSXMAAMM
-MSAMASMSMX
-XMASAMXAMM
-XXAMMXXAMA
-SMSMSASXSS
-SAXAMASAAA
-MAMMMXMMMM
-MXMXAXMASX";
-
-    #[test]
-    fn p1() {
-        assert_eq!(18, pt1(INPUT));
-    }
-
-    #[test]
-    fn p2() {
-        assert_eq!(9, pt2(INPUT));
-    }
-}