Day 11

Cargo.lock

@@ -88,3 +88,11 @@ dependencies = [
 [[package]]
 name = "d10t2"
 version = "0.1.0"
+
+[[package]]
+name = "d11t1"
+version = "0.1.0"
+
+[[package]]
+name = "d11t2"
+version = "0.1.0"

Cargo.toml

@@ -23,4 +23,6 @@ members = [
     "d09t2",
     "d10t1",
     "d10t2",
+    "d11t1",
+    "d11t2",
 ]

d11t1/Cargo.toml

@@ -0,0 +1,8 @@
+[package]
+name = "d11t1"
+version = "0.1.0"
+edition = "2021"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]

d11t1/demo_input.txt

@@ -0,0 +1,10 @@
+...#......
+.......#..
+#.........
+..........
+......#...
+.#........
+.........#
+..........
+.......#..
+#...#.....

d11t1/src/main.rs

@@ -0,0 +1,70 @@
+use std::fs::read_to_string;
+
+fn main() {
+    let input = read_to_string("input.txt").unwrap();
+    println!("d11t1: {}", d11t1(&input));
+}
+
+#[derive(Clone, Copy, Debug)]
+struct Galaxy {
+    col: usize,
+    row: usize,
+}
+
+#[must_use]
+pub fn d11t1(input: &str) -> usize {
+    let lines = input.lines();
+    let width = lines.clone().next().unwrap().len();
+    let mut expanded_lines = Vec::<String>::new();
+    for line in lines {
+        if line.chars().all(|c| c == '.') {
+            expanded_lines.push(".".repeat(width));
+        }
+        expanded_lines.push(line.to_string());
+    }
+    let mut fields = vec![String::new(); expanded_lines.len()];
+    let expanded_lines = expanded_lines
+        .into_iter()
+        .map(|l| l.chars().collect::<Vec<char>>())
+        .collect::<Vec<_>>();
+    for col in 0..width {
+        if expanded_lines.iter().all(|row| row[col] == '.') {
+            for (row_idx, row) in expanded_lines.iter().enumerate() {
+                fields[row_idx].extend(['.', row[col]]);
+            }
+        } else {
+            for (row_idx, row) in expanded_lines.iter().enumerate() {
+                fields[row_idx].extend([row[col]]);
+            }
+        }
+    }
+    let galaxies = fields
+        .iter()
+        .enumerate()
+        .flat_map(|(row, line)| {
+            line.chars()
+                .enumerate()
+                .filter(|&(_col, c)| c == '#')
+                .map(move |(col, _)| Galaxy { col, row })
+        })
+        .collect::<Vec<_>>();
+    let mut res = 0;
+    for (idx, galaxy) in galaxies.clone().into_iter().enumerate() {
+        res += galaxies
+            .iter()
+            .skip(idx + 1)
+            .map(|g| g.col.abs_diff(galaxy.col) + g.row.abs_diff(galaxy.row))
+            .sum::<usize>();
+    }
+    res
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    #[test]
+    fn test_d11t1() {
+        let input = include_str!("../demo_input.txt");
+        assert_eq!(d11t1(input), 374);
+    }
+}

d11t2/Cargo.toml

@@ -0,0 +1,8 @@
+[package]
+name = "d11t2"
+version = "0.1.0"
+edition = "2021"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]

d11t2/demo_input.txt

@@ -0,0 +1,10 @@
+...#......
+.......#..
+#.........
+..........
+......#...
+.#........
+.........#
+..........
+.......#..
+#...#.....

d11t2/src/main.rs

@@ -0,0 +1,75 @@
+use std::fs::read_to_string;
+
+fn main() {
+    let input = read_to_string("input.txt").unwrap();
+    println!("d11t2: {}", d11t2(&input, 1_000_000));
+}
+
+#[derive(Clone, Copy, Debug)]
+struct Galaxy {
+    col: usize,
+    row: usize,
+}
+
+#[must_use]
+pub fn d11t2(input: &str, factor: usize) -> usize {
+    let lines = input.lines();
+    let width = lines.clone().next().unwrap().len();
+
+    let fields = lines
+        .into_iter()
+        .map(|l| l.chars().collect::<Vec<char>>())
+        .collect::<Vec<_>>();
+    let empty_rows = fields
+        .iter()
+        .enumerate()
+        .filter(|(_, row)| row.iter().all(|c| *c == '.'))
+        .map(|(idx, _)| idx)
+        .collect::<Vec<_>>();
+    let empty_cols = (0..width)
+        .filter(|&col| fields.iter().all(|row| row[col] == '.'))
+        .collect::<Vec<_>>();
+    let galaxies = fields
+        .iter()
+        .enumerate()
+        .flat_map(|(row, line)| {
+            line.iter()
+                .enumerate()
+                .filter(|&(_col, c)| *c == '#')
+                .map(move |(col, _)| Galaxy { col, row })
+        })
+        .collect::<Vec<_>>();
+    let get_distances = |(a, b): (Galaxy, Galaxy)| -> usize {
+        a.col.abs_diff(b.col)
+            + a.row.abs_diff(b.row)
+            + (((a.col.min(b.col))..=(a.col.max(b.col)))
+                .filter(|col| empty_cols.contains(col))
+                .count()
+                + ((a.row.min(b.row))..=(a.row.max(b.row)))
+                    .filter(|row| empty_rows.contains(row))
+                    .count())
+                * (factor - 1)
+    };
+    galaxies
+        .clone()
+        .into_iter()
+        .enumerate()
+        .flat_map(|(idx, galaxy)| galaxies.iter().skip(idx + 1).map(move |g| (galaxy, *g)))
+        .map(get_distances)
+        .sum::<usize>()
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    #[test]
+    fn test_d11t2_10() {
+        let input = include_str!("../demo_input.txt");
+        assert_eq!(d11t2(input, 10), 1030);
+    }
+    #[test]
+    fn test_d11t2_100() {
+        let input = include_str!("../demo_input.txt");
+        assert_eq!(d11t2(input, 100), 8410);
+    }
+}