Day 17

inputs/day17.txt

@@ -0,0 +1,8 @@
+.......#
+....#...
+...###.#
+#...###.
+....##..
+##.#..#.
+###.#.#.
+....#...

inputs/day17_test.txt

@@ -0,0 +1,3 @@
+.#.
+..#
+###

src/bin/conway_cube.rs

@@ -0,0 +1,224 @@
+use advent2020::errors::{MapParseError, TopLevelError};
+use std::collections::HashSet;
+use std::env;
+use std::fmt;
+use std::fs;
+use std::ops::RangeInclusive;
+use std::str::FromStr;
+
+struct ConwayCube {
+    x_range: RangeInclusive<isize>,
+    y_range: RangeInclusive<isize>,
+    z_range: RangeInclusive<isize>,
+    active_points: HashSet<(isize, isize, isize)>,
+}
+
+impl ConwayCube {
+    fn is_active(&self, x: isize, y: isize, z: isize) -> bool {
+        self.active_points.contains(&(x, y, z))
+    }
+
+    fn active_neighbors(&self, x: isize, y: isize, z: isize) -> usize {
+        let mut count = 0;
+
+        for x_offset in -1..=1 {
+            for y_offset in -1..=1 {
+                for z_offset in -1..=1 {
+                    if (x_offset != 0) || (y_offset != 0) || (z_offset != 0) {
+                        if self.is_active(x + x_offset, y + y_offset, z + z_offset) {
+                            count += 1;
+                        }
+                    }
+                }
+            }
+        }
+
+        count
+    }
+
+    fn next(&self) -> ConwayCube {
+        let x_range = (self.x_range.start() - 1)..=(self.x_range.end() + 1);
+        let y_range = (self.y_range.start() - 1)..=(self.y_range.end() + 1);
+        let z_range = (self.z_range.start() - 1)..=(self.z_range.end() + 1);
+        let mut active_points = HashSet::new();
+
+        for x in x_range.clone() {
+            for y in y_range.clone() {
+                for z in z_range.clone() {
+                    let active_neighbors = self.active_neighbors(x, y, z);
+
+                    if self.is_active(x, y, z) && (active_neighbors == 2 || active_neighbors == 3) {
+                        active_points.insert((x, y, z));
+                    } else {
+                        if self.active_neighbors(x, y, z) == 3 {
+                            active_points.insert((x, y, z));
+                        }
+                    }
+                }
+            }
+        }
+
+        ConwayCube { x_range, y_range, z_range, active_points }
+    }
+}
+
+impl FromStr for ConwayCube {
+    type Err = TopLevelError;
+
+    fn from_str(contents: &str) -> Result<Self, Self::Err> {
+        let mut computed_width = None;
+        let mut data = Vec::new();
+
+        for line in contents.lines() {
+            let start_size = data.len();
+            for char in line.chars() {
+                match char {
+                    '.' => data.push(false),
+                    '#' => data.push(true),
+                    _ => return Err(MapParseError::UnexpectedCharacter(char))?,
+                }
+            }
+
+            match computed_width {
+                None => computed_width = Some(data.len()),
+                Some(first_width) if data.len() - start_size == first_width => {}
+                Some(first_width) => return Err(MapParseError::UnevenLines(first_width))?,
+            }
+        }
+
+        let width = computed_width.ok_or(TopLevelError::NoInputFound)? as isize;
+        let height = data.len() as isize / width;
+
+        if width != height {
+            return Err(TopLevelError::MapParseError(MapParseError::UnevenLines(width as usize)));
+        }
+
+        let x_range = 0..=(width-1);
+        let y_range = 0..=(height-1);
+        let z_range = 0..=0;
+        let mut active_points = HashSet::new();
+
+        let mut data_points = data.iter();
+        for y in y_range.clone() {
+            for x in x_range.clone() {
+                if *data_points.next().ok_or(TopLevelError::UnknownError)? {
+                    active_points.insert((x, y, 0));
+                }
+            }
+        }
+
+        Ok(ConwayCube { x_range, y_range, z_range, active_points })
+    }
+}
+
+impl fmt::Display for ConwayCube {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        for z in self.z_range.clone() {
+            write!(f, "z={}\n", z)?;
+            for y in self.y_range.clone() {
+                for x in self.x_range.clone() {
+                    if self.is_active(x, y, z) {
+                        write!(f, "#")?;
+                    } else {
+                        write!(f, ".")?;
+                    }
+                }
+                write!(f, "\n")?;
+            }
+        }
+        Ok(())
+    }
+}
+struct Conway4Cube {
+    x_range: RangeInclusive<isize>,
+    y_range: RangeInclusive<isize>,
+    z_range: RangeInclusive<isize>,
+    w_range: RangeInclusive<isize>,
+    active_points: HashSet<(isize, isize, isize, isize)>,
+}
+
+impl Conway4Cube {
+    fn is_active(&self, x: isize, y: isize, z: isize, w: isize) -> bool {
+        self.active_points.contains(&(x, y, z, w))
+    }
+
+    fn active_neighbors(&self, x: isize, y: isize, z: isize, w: isize) -> usize {
+        let mut count = 0;
+
+        for x_offset in -1..=1 {
+            for y_offset in -1..=1 {
+                for z_offset in -1..=1 {
+                    for w_offset in -1..=1 {
+                        if (x_offset != 0) || (y_offset != 0) || (z_offset != 0) || (w_offset != 0) {
+                            if self.is_active(x + x_offset, y + y_offset, z + z_offset, w + w_offset) {
+                                count += 1;
+                            }
+                        }
+                    }
+                }
+            }
+        }
+
+        count
+    }
+
+    fn next(&self) -> Conway4Cube {
+        let x_range = (self.x_range.start() - 1)..=(self.x_range.end() + 1);
+        let y_range = (self.y_range.start() - 1)..=(self.y_range.end() + 1);
+        let z_range = (self.z_range.start() - 1)..=(self.z_range.end() + 1);
+        let w_range = (self.w_range.start() - 1)..=(self.w_range.end() + 1);
+
+        let mut active_points = HashSet::new();
+
+        for x in x_range.clone() {
+            for y in y_range.clone() {
+                for z in z_range.clone() {
+                    for w in w_range.clone() {
+                        let active_neighbors = self.active_neighbors(x, y, z, w);
+
+                        if self.is_active(x, y, z, w) && (active_neighbors == 2 || active_neighbors == 3) {
+                            active_points.insert((x, y, z, w));
+                        } else {
+                            if self.active_neighbors(x, y, z, w) == 3 {
+                                active_points.insert((x, y, z, w));
+                            }
+                        }
+                    }
+                }
+            }
+        }
+
+        Conway4Cube { x_range, y_range, z_range, w_range, active_points }
+    }
+}
+
+impl<'a> From<&'a ConwayCube> for Conway4Cube {
+    fn from(x: &ConwayCube) -> Conway4Cube {
+        Conway4Cube {
+            x_range: x.x_range.clone(),
+            y_range: x.x_range.clone(),
+            z_range: x.x_range.clone(),
+            w_range: 0..=0,
+            active_points: x.active_points.iter().map(|(x,y,z)| (*x, *y, *z, 0)).collect(),
+        }
+    }
+}
+
+fn main() -> Result<(), TopLevelError> {
+    let filename = env::args().nth(1).expect("No file argument given.");
+    let contents = fs::read_to_string(filename)?;
+    let mut cube = ConwayCube::from_str(&contents)?;
+    let mut cube4 = Conway4Cube::from(&cube);
+
+    for _ in 0..6 {
+        //println!("-------------------------------------------------");
+        //println!("{}\n", cube);
+        cube = cube.next();
+        cube4 = cube4.next();
+    }
+
+    println!("Active 3-dimensional points in the end: {}", cube.active_points.len());
+    println!("Active 4-dimensional points in the end: {}", cube4.active_points.len());
+
+    Ok(())
+}