day 25

src/day25.rs

@@ -0,0 +1,117 @@
+use std::fs::read_to_string;
+
+use itertools::Itertools;
+
+pub fn day_main() {
+    let input = read_to_string("input/day25.txt").unwrap();
+    let input = input.trim();
+    println!(" part1: {}", part1(input));
+}
+
+type RiddleResult = i64;
+
+fn part1(input: &str) -> RiddleResult {
+    let (locks, keys): (Vec<_>, Vec<_>) = input
+        .split("\n\n")
+        .map(|item| {
+            let block = item
+                .lines()
+                .map(|line| line.chars().collect_vec())
+                .collect_vec();
+            let lock = block[0].contains(&'#');
+            let summary: (u8, u8, u8, u8, u8) = if lock {
+                // lock
+                (0..5)
+                    .map(|x| {
+                        (0..6)
+                            .map(|y| block[y][x])
+                            .enumerate()
+                            .find(|(_, it)| *it == '.')
+                            .unwrap_or((6, '.'))
+                            .0 as u8
+                    })
+                    .collect_tuple()
+                    .unwrap()
+            } else {
+                (0..5)
+                    .map(|x| {
+                        7 - ((0..6)
+                            .map(|y| block[y][x])
+                            .enumerate()
+                            .find(|(_, it)| *it == '#')
+                            .unwrap_or((6, '.'))
+                            .0 as u8)
+                    })
+                    .collect_tuple()
+                    .unwrap()
+            };
+            (lock, summary.0, summary.1, summary.2, summary.3, summary.4)
+        })
+        .partition(|s| s.0);
+
+    let mut matches = 0;
+    for lock in locks {
+        for &key in &keys {
+            if lock.1 + key.1 < 8
+                && lock.2 + key.2 < 8
+                && lock.3 + key.3 < 8
+                && lock.4 + key.4 < 8
+                && lock.5 + key.5 < 8
+            {
+                matches += 1;
+            }
+        }
+    }
+    matches
+}
+
+#[cfg(test)]
+mod test {
+    use super::part1;
+
+    const TEST_INPUT: &str = r"#####
+.####
+.####
+.####
+.#.#.
+.#...
+.....
+
+#####
+##.##
+.#.##
+...##
+...#.
+...#.
+.....
+
+.....
+#....
+#....
+#...#
+#.#.#
+#.###
+#####
+
+.....
+.....
+#.#..
+###..
+###.#
+###.#
+#####
+
+.....
+.....
+.....
+#....
+#.#..
+#.#.#
+#####
+    ";
+
+    #[test]
+    fn test1() {
+        assert_eq!(part1(TEST_INPUT), 3);
+    }
+}

src/lib.rs

@@ -19,5 +19,6 @@ pub mod day19;
 pub mod day22;
 pub mod day23;
 pub mod day24;
+pub mod day25;
 // PLACEHOLDER
 pub mod utils;

src/main.rs

@@ -27,6 +27,7 @@ fn main() {
         (23, day23::day_main),
         (23, day23::day_main),
         (24, day24::day_main),
+        (25, day25::day_main),
         // PLACEHOLDER
     ]);
     let day: Option<u8> = args().nth(1).and_then(|a| a.parse().ok());