8th day

Author: majcn

data/examples/08.txt

@@ -0,0 +1,12 @@
+............
+........0...
+.....0......
+.......0....
+....0.......
+......A.....
+............
+............
+........A...
+.........A..
+............
+............

src/bin/08.rs

@@ -0,0 +1,117 @@
+advent_of_code::solution!(8);
+
+use advent_of_code::maneatingape::hash::*;
+use advent_of_code::maneatingape::point::*;
+
+struct MapSize {
+    min_x: i32,
+    max_x: i32,
+    min_y: i32,
+    max_y: i32,
+}
+
+struct DataType {
+    data: FastMap<u8, Vec<Point>>,
+    map_size: MapSize,
+}
+
+impl MapSize {
+    fn contains(&self, point: &Point) -> bool {
+        point.x >= self.min_x
+            && point.x <= self.max_x
+            && point.y >= self.min_y
+            && point.y <= self.max_y
+    }
+}
+
+fn parse_data(input: &str) -> DataType {
+    let mut data = FastMap::new();
+
+    let width = input.lines().next().unwrap().len() as i32;
+    let height = input.lines().count() as i32;
+
+    for (y, line) in input.lines().enumerate() {
+        for (x, c) in line.bytes().enumerate() {
+            if c != b'.' {
+                (*data.entry(c).or_insert(vec![])).push(Point::new(x as i32, y as i32));
+            }
+        }
+    }
+
+    DataType {
+        data: data,
+        map_size: MapSize {
+            min_x: 0,
+            max_x: width - 1,
+            min_y: 0,
+            max_y: height - 1,
+        },
+    }
+}
+
+fn part_x(data: DataType, unlimited: bool) -> u32 {
+    let DataType { data, map_size } = data;
+
+    let mut antinodes = FastSet::new();
+    for (_, v) in data {
+        for i in 0..v.len() {
+            for j in 0..v.len() {
+                if i == j {
+                    continue;
+                }
+
+                let p1 = v[i];
+                let p2 = v[j];
+
+                let diff = p2 - p1;
+                if unlimited {
+                    let mut new_point = p2;
+                    while map_size.contains(&new_point) {
+                        antinodes.insert(new_point);
+                        new_point += diff;
+                    }
+                } else {
+                    let new_point = p2 + diff;
+                    if map_size.contains(&new_point) {
+                        antinodes.insert(new_point);
+                    }
+                }
+            }
+        }
+    }
+
+    antinodes.len() as u32
+}
+
+pub fn part_one(input: &str) -> Option<u32> {
+    let data = parse_data(input);
+
+    let result = part_x(data, false);
+
+    Some(result)
+}
+
+pub fn part_two(input: &str) -> Option<u32> {
+    let data = parse_data(input);
+
+    let result = part_x(data, true);
+
+    Some(result)
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_part_one() {
+        let result = part_one(&advent_of_code::template::read_file("examples", DAY));
+        assert_eq!(result, Some(14));
+    }
+
+    #[test]
+    fn test_part_two() {
+        let result = part_two(&advent_of_code::template::read_file("examples", DAY));
+        assert_eq!(result, Some(34));
+    }
+}