solution: day 13

data/examples/13.txt

@@ -0,0 +1,15 @@
+#.##..##.
+..#.##.#.
+##......#
+##......#
+..#.##.#.
+..##..##.
+#.#.##.#.
+
+#...##..#
+#....#..#
+..##..###
+#####.##.
+#####.##.
+..##..###
+#....#..#

src/bin/13.rs

@@ -0,0 +1,66 @@
+fn mirror_h(shape: &Vec<Vec<char>>, smudges: usize) -> Option<usize> {
+    (1..shape.len())
+        .filter(|&i| {
+            shape
+                .iter()
+                .skip(i)
+                .zip(shape.iter().take(i).rev())
+                .map(|(x, y)| {
+                    x.iter()
+                        .zip(y.iter())
+                        .map(|(xx, yy)| (xx != yy) as usize)
+                        .sum::<usize>()
+                })
+                .sum::<usize>()
+                == smudges
+        })
+        .max()
+}
+fn mirror_v(shape: &Vec<Vec<char>>, smudges: usize) -> Option<usize> {
+    let shape = (0..shape[0].len())
+        .map(|col| (0..shape.len()).map(|row| shape[row][col]).collect())
+        .collect();
+
+    mirror_h(&shape, smudges)
+}
+
+fn solve(input: &str, smudges: usize) -> usize {
+    input
+        .split("\n\n")
+        .map(|x| x.lines().map(|line| line.chars().collect()).collect())
+        .map(|shape| {
+            let v = mirror_v(&shape, smudges).unwrap_or_default();
+            let h = mirror_h(&shape, smudges).unwrap_or_default();
+            v + h * 100
+        })
+        .sum()
+}
+
+pub fn part_one(input: &str) -> Option<usize> {
+    Some(solve(input, 0))
+}
+
+pub fn part_two(input: &str) -> Option<usize> {
+    Some(solve(input, 1))
+}
+
+aoc::solution!(13);
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    #[test]
+    fn test_part_one() {
+        assert_eq!(
+            part_one(&aoc::template::read_file("examples", 13)),
+            Some(405)
+        );
+    }
+    #[test]
+    fn test_part_two() {
+        assert_eq!(
+            part_two(&aoc::template::read_file("examples", 13)),
+            Some(400)
+        );
+    }
+}