Day11 Rust

day11/rust/.gitignore

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+target

day11/rust/Cargo.lock

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+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+version = 3
+
+[[package]]
+name = "rust"
+version = "0.1.0"

day11/rust/Cargo.toml

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

day11/rust/src/main.rs

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+enum Tile {
+    Empty,
+    Galaxy,
+}
+
+#[derive(Clone)]
+#[derive(Debug)]
+struct Position {
+    x: usize,
+    y: usize,
+}
+
+fn main() {
+    let stdin = std::io::stdin();
+
+    let mut universe = Vec::new();
+
+    for line in stdin.lines() {
+        let line = line.unwrap();
+
+        let row: Vec<_> = line
+            .chars()
+            .map(|e| match e {
+                '.' => Tile::Empty,
+                '#' => Tile::Galaxy,
+                _ => unreachable!(),
+            })
+            .collect();
+
+        universe.push(row);
+    }
+
+    let mut original_galaxies = Vec::new();
+
+    for i in 0..universe.len() {
+        for j in 0..universe[i].len() {
+            if let Tile::Galaxy = universe[i][j] {
+                original_galaxies.push(Position { x: j, y: i })
+            }
+        }
+    }
+
+
+    let mut galaxies = original_galaxies.clone();
+
+    expand_universe(&universe, &mut galaxies, 2);
+
+    let mut part1 = 0;
+
+    for i in 0..galaxies.len() {
+        for j in i..galaxies.len() {
+            part1 += galaxies[i].x.abs_diff(galaxies[j].x);
+            part1 += galaxies[i].y.abs_diff(galaxies[j].y);
+        }
+    }
+
+    println!("{}", part1);
+
+    let mut galaxies = original_galaxies.clone();
+
+    expand_universe(&universe, &mut galaxies, 1_000_000);
+
+    let mut part2 = 0;
+
+    for i in 0..galaxies.len() {
+        for j in i..galaxies.len() {
+            part2 += galaxies[i].x.abs_diff(galaxies[j].x);
+            part2 += galaxies[i].y.abs_diff(galaxies[j].y);
+        }
+    }
+
+    println!("{}", part2);
+}
+
+fn expand_universe(
+    universe: &Vec<Vec<Tile>>,
+    galaxies: &mut Vec<Position>,
+    expansion_rate: usize,
+) -> () {
+    let mut galaxy_offsets = Vec::new();
+
+    for _ in 0..galaxies.len() {
+        galaxy_offsets.push(Position { x: 0, y: 0 });
+    }
+
+    for i in 0..universe.len() {
+        if universe[i].iter().all(|e| match e {
+            Tile::Empty => true,
+            _ => false,
+        }) {
+            for (j, galaxy) in galaxies.iter().enumerate() {
+                if galaxy.y > i {
+                    galaxy_offsets[j].y += expansion_rate - 1;
+                }
+            }
+        }
+    }
+
+    let mut columns = Vec::new();
+
+    for i in 0..universe[0].len() {
+        let mut column = Vec::new();
+        for j in 0..universe.len() {
+            column.push(&universe[j][i]);
+        }
+        columns.push(column);
+    }
+
+    for i in 0..columns.len() {
+        if columns[i].iter().all(|e| match e {
+            Tile::Empty => true,
+            _ => false,
+        }) {
+            for (j, galaxy) in galaxies.iter().enumerate() {
+                if galaxy.x > i {
+                    galaxy_offsets[j].x += expansion_rate - 1;
+                }
+            }
+        }
+    }
+
+    for (i, galaxy) in galaxies.iter_mut().enumerate() {
+        galaxy.x += galaxy_offsets[i].x;
+        galaxy.y += galaxy_offsets[i].y;
+    }
+}