cleanup

src/day04.rs

@@ -0,0 +1,116 @@
+use itertools::Itertools;
+use std::collections::HashMap;
+use std::fs::read_to_string;
+
+pub fn day_main() {
+    let input = read_to_string("input/day04.txt").unwrap();
+    let input = input.trim();
+    println!(" part1: {}", part1(input));
+    println!(" part2: {}", part2(input));
+}
+
+type RiddleResult = usize;
+
+fn part1(input: &str) -> RiddleResult {
+    let puzzle = parse_map(input);
+    let mut count = 0;
+    let x_max = puzzle.keys().map(|k| k.0).max().unwrap();
+    let y_max = puzzle.keys().map(|k| k.1).max().unwrap();
+
+    for sx in 0..=x_max {
+        for sy in 0..=y_max {
+            'foo: for (a, b) in [
+                (1, 1),
+                (-1, 1),
+                (1, -1),
+                (-1, -1),
+                (0, 1),
+                (1, 0),
+                (0, -1),
+                (-1, 0),
+            ] {
+                for (i, c) in "XMAS".chars().enumerate() {
+                    let i = i as i32;
+                    let p = (sx as i32 + i * a, sy as i32 + i * b);
+                    if p.0 < 0 || p.1 < 0 || p.0 > x_max as i32 || p.1 > y_max as i32 {
+                        continue 'foo;
+                    }
+
+                    if puzzle[&(p.0 as usize, p.1 as usize)] != c {
+                        continue 'foo;
+                    }
+                }
+                count += 1;
+            }
+        }
+    }
+
+    count
+}
+
+fn part2(input: &str) -> RiddleResult {
+    let puzzle = parse_map(input);
+    let mut count = 0;
+    let x_max = puzzle.keys().map(|k| k.0).max().unwrap();
+    let y_max = puzzle.keys().map(|k| k.1).max().unwrap();
+    for sx in 1..x_max {
+        for sy in 1..y_max {
+            let first = [
+                puzzle[&(sx - 1, sy - 1)],
+                puzzle[&(sx, sy)],
+                puzzle[&(sx + 1, sy + 1)],
+            ]
+            .into_iter()
+            .join("");
+            let second = [
+                puzzle[&(sx - 1, sy + 1)],
+                puzzle[&(sx, sy)],
+                puzzle[&(sx + 1, sy - 1)],
+            ]
+            .into_iter()
+            .join("");
+            if (first == "MAS" || first == "SAM") && (second == "SAM" || second == "MAS") {
+                count += 1;
+            }
+        }
+    }
+
+    count
+}
+
+fn parse_map(input: &str) -> HashMap<(usize, usize), char> {
+    let mut puzzle = HashMap::<(usize, usize), char>::new();
+    input.lines().enumerate().for_each(|(y, line)| {
+        line.chars().enumerate().for_each(|(x, chr)| {
+            puzzle.insert((x, y), chr);
+        })
+    });
+    puzzle
+}
+
+#[cfg(test)]
+mod test {
+    use super::{part1, part2};
+
+    const TEST_INPUT: &str = r"MMMSXXMASM
+MSAMXMSMSA
+AMXSXMAAMM
+MSAMASMSMX
+XMASAMXAMM
+XXAMMXXAMA
+SMSMSASXSS
+SAXAMASAAA
+MAMMMXMMMM
+MXMXAXMASX
+";
+
+    #[test]
+    fn test1() {
+        assert_eq!(part1(TEST_INPUT), 18);
+    }
+
+    #[test]
+    fn test2() {
+        assert_eq!(part2(TEST_INPUT), 9);
+    }
+}

src/lib.rs

@@ -1,3 +1,4 @@
 pub mod day01;
 pub mod day02;
 pub mod day03;
+pub mod day04;

src/main.rs

@@ -8,6 +8,7 @@ fn main() {
         (1, day01::day_main as fn()),
         (2, day02::day_main),
         (3, day03::day_main),
+        (4, day04::day_main),
     ]);
     let day: Option<u8> = args().nth(1).and_then(|a| a.parse().ok());
     let Some(day) = day else {

src/template.rs

@@ -0,0 +1,35 @@
+use std::fs::read_to_string;
+
+pub fn day_main() {
+    let input = read_to_string("input/dayXX.txt").unwrap();
+    let input = input.trim();
+    println!(" part1: {}", part1(input));
+    println!(" part2: {}", part2(input));
+}
+
+type RiddleResult = i64;
+
+fn part1(input: &str) -> RiddleResult {
+    0
+}
+
+fn part2(_input: &str) -> RiddleResult {
+    0
+}
+
+#[cfg(test)]
+mod test {
+    use super::{part1, part2};
+
+    const TEST_INPUT: &str = r"";
+
+    #[test]
+    fn test1() {
+        assert_eq!(part1(TEST_INPUT), 0);
+    }
+
+    #[test]
+    fn test2() {
+        assert_eq!(part2(TEST_INPUT), 0);
+    }
+}