Day 11

Cargo.lock

@@ -15,9 +15,25 @@ dependencies = [
 name = "aoc23"
 version = "0.1.0"
 dependencies = [
+ "itertools",
  "regex",
 ]
 
+[[package]]
+name = "either"
+version = "1.9.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a26ae43d7bcc3b814de94796a5e736d4029efb0ee900c12e2d54c993ad1a1e07"
+
+[[package]]
+name = "itertools"
+version = "0.12.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "25db6b064527c5d482d0423354fcd07a89a2dfe07b67892e62411946db7f07b0"
+dependencies = [
+ "either",
+]
+
 [[package]]
 name = "memchr"
 version = "2.6.4"

Cargo.toml

@@ -7,3 +7,4 @@ edition = "2021"
 
 [dependencies]
 regex = "1.10"
+itertools = "0.12"

input/day11.txt

@@ -0,0 +1,140 @@
+.......#.....#.....................#.............#.................#.........................#..............................................
+#.....................#.......#.................................................................................#.......#...................
+.......................................................................#.........................#..................................#.......
+................................................................#..............#..............................................#.............
+.........................................#............................................................#....................................#
+.................#..................................................#.......................................................................
+...........................#...............................................................................#................................
+....#.......#...........................................#..........................#.............................#..........................
+....................#.............#........#................................................................................................
+...................................................#...................................................#...................#................
+.........................#........................................#..................................................#......................
+......#..........#...........................................#...........#............#.....................................................
+......................................#..........................................#.........................#.....................#..........
+.#...................#..................................#.......................................#...........................................
+............#.................................#.....................#.......................................................................
+............................................................................................................................................
+..............................#.....................................................................................#..................#....
+....................................................................................#........#......#.......................................
+.........................#.........................#............#...........................................#...............................
+.#......#.....#.......................#.................#........................................................#.....#....................
+...........................................................................#.................................................#..............
+...............................................#.......................................#...............#..........................#.........
+......................#..................#..................................................................................................
+..........................................................................................................................#.................
+......#...........................#.........................................................#........................#......................
+..............................................................................................................................#.............
+..#.......................#.................#............................................................................................#..
+..................#....................................................#................#...................................................
+....................................................#.....#....................#............................................................
+...............................#............................................................................................................
+..............................................#...............#..........................................................#...........#......
+.#.........#........................#..................................................................#....................................
+..........................................................................#.......................#........................................#
+...................#......................................................................#.................................................
+.............................................................................................................................#..............
+.....#......................................................................................................................................
+........................................................#........................#..........................................................
+.............................#...............#.....................#.....#............#..................#..............................#...
+............................................................................................#......#...........#............................
+.........................#........#...................................................................................#.....................
+...........................................................................................................................................#
+.....................................................#.....#.................................................................#..............
+#.........................................................................................................#.......................#.........
+................#...........................................................#.....................#.........................................
+..............................#..............#...................................#.......#...........................#......................
+........#................#.........#............................#............................................#.............#.........#......
+............................................................................................................................................
+.......................................................#...............#.............................#...........................#..........
+.............#.................................#............................................................................................
+............................................................................................................................................
+..#.............................................................................#...........................................#...........#...
+............................................................................................................................................
+......................................#..........................................................#................#.........................
+............................#................#......#......................#...........#....................................................
+............................................................................................................................................
+....................................................................................................#................#..........#...........
+.#............#...................#...............................#........................................#.............................#..
+.........#...............................................................#..................................................................
+.......................#....................#........#...........................................#..........................................
+............................................................#.....................................................#.........................
+..............................#.......................................................................#...................#.......#.........
+............#.......................#...................#............................#......................................................
+...................................................#......................................#..............................................#..
+.#................#...................................................#........................#............................................
+......#....................................................................#................................#...............................
+...............................#....................................................................................#.......................
+.........................#.....................#......#.............................................#.................................#.....
+............................................................................................................................................
+...............#.....................#....................................................#.................................................
+..................................................................................................................#.........................
+....#......#.....................................#..............................#............................#............#.....#...........
+....................#.............................................#....................#.........#.......................................#..
+.........................................................#..............#.............................#.....................................
+............................#...........#...........................................................................#.......................
+............................................................................................................................................
+#..................................#...............................................................#..........#.............................
+.......#......................................................................................#.................................#.......#...
+.....................#....................#...............................#.....#......................................#....................
+................................#..........................#......#....................#..........................#.........................
+..............#...................................#........................................................................#...............#
+....#....................................................................................................#..................................
+.......................#....................................................................................................................
+......................................#................................#..................#.................................................
+.....................................................#............................................#...............................#.........
+............................................................................................................................................
+............................................................................................................................................
+....#.................#..................................#.........................#..........................#.............................
+.............#........................................................................................#..................#..................
+......................................#............................................................................#........................
+.........#....................................................#.........#............................................................#......
+.............................................................................................#..............................................
+.............................#...........#............................................................................#.....................
+#..................#................................................#....................#.......................................#.........#
+...................................................................................................#......#.................................
+...........#.............................................#...........................#......................................................
+....................................#.......................................................................................................
+..................................................#..........#.........#......................#.....................#.......................
+.#......#....................................#..............................................................#...............................
+.............................#.............................................#................................................................
+.......................#...............................................................................#....................#...............
+....................................................#.....................................#...........................................#.....
+................#.....................#..................#.................................................................................#
+...#.....#..........................................................#................#......................................................
+.............................................#...............#................................#......#......................................
+...............................#...............................................#............................................................
+.............................................................................................................................#.........#....
+.....................#................................................#.................................................#...................
+...............#.........................#.......................#..................#.......................................................
+.....#......................................................................................................#.......................#.......
+....................................#.................#.........................#..................#........................................
+........................................................................................................................................#...
+.........#..............#.....................................#........................................#.....................#..............
+...............................................#...................#........................................................................
+......................................#.............#..................................#.....#.......................#......................
+............#.....#...............................................................................#.........................................
+...#...................................................................................................................................#....
+.......................#.........................#..........................................................................................
+.........................................................#...........#.........................#........#..........#.............#..........
+............................#..............#....................#........................................................#..................
+.......#.................................................................#................#.................................................
+.................#..................................................................................#........................#...........#..
+...................................................#.......#................................................................................
+.........................................#......................................#......................................#....................
+....................................#...........................................................................#...........................
+..............................#.............................................................#...........#.......................#......#....
+.........#...............................................#..............#...................................................................
+........................#....................#.....................................#........................................................
+#...........................................................................................................................................
+............................#......................................................................#.......#................................
+......................................#.....................................................................................................
+.....#............#.........................................#..........................#..........................................#.........
+...........................................#......................#..............................................#..........................
+..............#..............................................................................#............................#.............#...
+..#......#...........................................#..............................#..................#.....#..............................
+....................#..........#.....#...............................#......................................................................
+............................................................................................................................................
+.................................................#..........................................................................................
+.............#..........#...............................#...............#.............#..........#.........#........#.......................
+............................................#................#.................#............................................................
+....................................#....................................................................................#.............#....

src/day11.rs

@@ -0,0 +1,122 @@
+use itertools::Itertools;
+use std::fmt::Debug;
+
+pub fn run() {
+    let input = include_str!("../input/day11.txt");
+    // let input = r#"...#......
+    // .......#..
+    // #.........
+    // ..........
+    // ......#...
+    // .#........
+    // .........#
+    // ..........
+    // .......#..
+    // #...#....."#;
+    let image: Image = input.into();
+    let expansions = image.expand();
+
+    dbg!(calculate_distances(&image, &expansions, 2));
+    dbg!(calculate_distances(&image, &expansions, 1_000_000));
+}
+
+fn calculate_distances(image: &Image, expansions: &Expansions, factor: usize) -> usize {
+    image
+        .iter_galaxies()
+        .combinations(2)
+        .map(|v| expansions.distance(factor, v[0], v[1]))
+        .sum::<usize>()
+}
+
+#[derive(Clone)]
+struct Image {
+    chars: Vec<Vec<char>>,
+    width: usize,
+    height: usize,
+}
+
+impl From<&str> for Image {
+    fn from(value: &str) -> Self {
+        let chars = value
+            .trim()
+            .lines()
+            .map(|l| l.trim().chars().collect::<Vec<_>>())
+            .collect::<Vec<_>>();
+        let width = chars[0].len();
+        let height = chars.len();
+        Self {
+            chars,
+            width,
+            height,
+        }
+    }
+}
+
+impl Debug for Image {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        let s = self
+            .chars
+            .iter()
+            .map(|row| row.iter().collect::<String>())
+            .collect::<Vec<_>>()
+            .join("\n");
+        write!(f, "Image(\n{})", s)
+    }
+}
+
+impl Image {
+    fn at(&self, col: usize, row: usize) -> char {
+        if col < self.chars[0].len() && row < self.chars.len() {
+            self.chars[row][col]
+        } else {
+            '.'
+        }
+    }
+
+    fn expand(&self) -> Expansions {
+        let rows = (0..self.height)
+            .rev()
+            .filter(|&row| (0..self.width).all(|col| self.at(col, row) == '.'))
+            .collect::<Vec<_>>();
+
+        let cols = (0..self.width)
+            .rev()
+            .filter(|&col| (0..self.height).all(|row| self.at(col, row) == '.'))
+            .collect::<Vec<_>>();
+
+        Expansions { rows, cols }
+    }
+
+    fn iter_galaxies<'a>(&'a self) -> impl Iterator<Item = (usize, usize)> + 'a {
+        (0..self.height)
+            .into_iter()
+            .flat_map(|row| (0..self.width).into_iter().map(move |col| (col, row)))
+            .filter(|(col, row)| self.at(*col, *row) == '#')
+    }
+}
+
+#[derive(Debug, Clone)]
+struct Expansions {
+    rows: Vec<usize>,
+    cols: Vec<usize>,
+}
+
+impl Expansions {
+    fn distance(&self, factor: usize, (x1, y1): (usize, usize), (x2, y2): (usize, usize)) -> usize {
+        let min_x = x1.min(x2);
+        let max_x = x1.max(x2);
+        let min_y = y1.min(y2);
+        let max_y = y1.max(y2);
+        let expanded_rows = self
+            .rows
+            .iter()
+            .filter(|row| (min_y..=max_y).contains(row))
+            .count();
+        let expanded_cols = self
+            .cols
+            .iter()
+            .filter(|col| (min_x..=max_x).contains(col))
+            .count();
+        (max_x - min_x) + (max_y - min_y) + (expanded_rows + expanded_cols) * (factor - 1)
+    }
+}

src/main.rs

@@ -11,7 +11,8 @@ mod day07;
 mod day08;
 mod day09;
 mod day10;
+mod day11;
 
 fn main() {
-    day10::run();
+    day11::run();
 }