src/day17.rs

@@ -1,101 +1,6 @@
 use aoc_runner_derive::aoc;
-use std::collections::HashSet;
 
 #[aoc(day17, part1)]
 fn solve_d17_p1(input: &str) -> usize {
-    let mut world = HashSet::new();
+    42
-    for (y, line) in input.split('\n').enumerate() {
-        for (x, _) in line
-            .as_bytes()
-            .iter()
-            .copied()
-            .enumerate()
-            .filter(|&(_, byte)| byte == b'#')
-        {
-            world.insert((x as isize, y as isize, 0isize, 0isize));
-        }
-    }
-    for _ in 0..6 {
-        world = step(world);
-    }
-    world.len()
-}
-
-fn neighbors(
-    world: &HashSet<(isize, isize, isize, isize)>,
-    (x, y, z, w): (isize, isize, isize, isize),
-) -> usize {
-    let mut count = 0;
-    for xa in x - 1..=x + 1 {
-        for ya in y - 1..=y + 1 {
-            for za in z - 1..=z + 1 {
-                for wa in w - 1..=w + 1 {
-                    count += world.contains(&(xa, ya, za, wa)) as usize;
-                }
-            }
-        }
-    }
-    count - world.contains(&(x, y, z, w)) as usize
-}
-
-fn step(world: HashSet<(isize, isize, isize, isize)>) -> HashSet<(isize, isize, isize, isize)> {
-    struct MinMax {
-        x_min: isize,
-        x_max: isize,
-        y_min: isize,
-        y_max: isize,
-        z_min: isize,
-        z_max: isize,
-        w_min: isize,
-        w_max: isize,
-    }
-    let MinMax {
-        x_min,
-        x_max,
-        y_min,
-        y_max,
-        z_min,
-        z_max,
-        w_min,
-        w_max,
-    } = world.iter().fold(
-        MinMax {
-            x_min: isize::MAX,
-            x_max: isize::MIN,
-            y_min: isize::MAX,
-            y_max: isize::MIN,
-            z_min: isize::MAX,
-            z_max: isize::MIN,
-            w_min: isize::MAX,
-            w_max: isize::MIN,
-        },
-        |minmax, &(x, y, z, w)| MinMax {
-            x_min: std::cmp::min(minmax.x_min, x),
-            x_max: std::cmp::max(minmax.x_max, x),
-            y_min: std::cmp::min(minmax.y_min, y),
-            y_max: std::cmp::max(minmax.y_max, y),
-            z_min: std::cmp::min(minmax.z_min, z),
-            z_max: std::cmp::max(minmax.z_max, z),
-            w_min: std::cmp::min(minmax.w_min, w),
-            w_max: std::cmp::max(minmax.w_max, w),
-        },
-    );
-    let mut new_world = HashSet::new();
-    for x in x_min - 1..=x_max + 1 {
-        for y in y_min - 1..=y_max + 1 {
-            for z in z_min - 1..=z_max + 1 {
-                for w in w_min - 1..=w_max + 1 {
-                    let active = world.contains(&(x, y, z, w));
-                    let n = neighbors(&world, (x, y, z, w));
-                    if active && (n == 2 || n == 3) {
-                        new_world.insert((x, y, z, w));
-                    }
-                    if !active && n == 3 {
-                        new_world.insert((x, y, z, w));
-                    }
-                }
-            }
-        }
-    }
-    new_world
 }