solution: day14

src/bin/14.rs

@@ -0,0 +1,118 @@
+use itertools::Itertools;
+use lazy_static::lazy_static;
+use regex::Regex;
+
+lazy_static! {
+    static ref RE: Regex = Regex::new(
+        r#"(?P<speed>\d+) km/s for (?P<duration>\d+) seconds, but then must rest for (?P<rest>\d+)"#
+    )
+    .unwrap();
+}
+
+const DISTANCE: u32 = 2503;
+
+struct Reindeer {
+    speed: u32,
+    duration: u32,
+    rest: u32,
+}
+
+impl Reindeer {
+    fn cycle(&self) -> u32 {
+        self.duration + self.rest
+    }
+
+    fn running(&self, traveled: u32) -> bool {
+        traveled % self.cycle() < self.duration
+    }
+}
+
+impl From<&str> for Reindeer {
+    fn from(value: &str) -> Self {
+        let cap = RE.captures(value).unwrap();
+
+        let speed = cap["speed"].parse().unwrap();
+        let duration = cap["duration"].parse().unwrap();
+        let rest = cap["rest"].parse().unwrap();
+
+        Self {
+            speed,
+            duration,
+            rest,
+        }
+    }
+}
+
+pub fn part_one(input: &str) -> Option<u32> {
+    input
+        .split('\n')
+        .map(|x| Reindeer::from(x))
+        .map(|y| {
+            ((DISTANCE / y.cycle()) * y.duration
+                + vec![DISTANCE % y.cycle(), y.duration].iter().min().unwrap())
+                * y.speed
+        })
+        .max()
+}
+
+#[derive(Clone, Debug)]
+struct Scoreboard {
+    current_distance: u32,
+    score: u32,
+}
+
+impl Scoreboard {
+    fn empty() -> Self {
+        Self {
+            current_distance: 0,
+            score: 0,
+        }
+    }
+}
+
+pub fn part_two(input: &str) -> Option<u32> {
+    let reindeers = input.split('\n').map(|x| Reindeer::from(x)).collect_vec();
+    let mut scoreboards = vec![Scoreboard::empty(); reindeers.len()];
+
+    for traveled in 0..DISTANCE {
+        for (idx, r) in reindeers
+            .iter()
+            .enumerate()
+            .filter(|(_, x)| x.running(traveled))
+        {
+            scoreboards[idx].current_distance += r.speed;
+        }
+
+        let win = scoreboards
+            .iter()
+            .map(|x| x.current_distance)
+            .max()
+            .unwrap();
+
+        for r in scoreboards.iter_mut().filter(|x| x.current_distance == win) {
+            r.score += 1;
+        }
+    }
+    scoreboards.iter().map(|x| x.score).max()
+}
+
+fn main() {
+    let input = &aoc::read_file("inputs", 14);
+    RE.captures(input);
+    aoc::solve!(1, part_one, input);
+    aoc::solve!(2, part_two, input);
+}
+#[cfg(test)]
+mod tests {
+    use super::*;
+    #[test]
+    fn test_part_one() {
+        let input = aoc::read_file("test_inputs", 14);
+        assert_eq!(part_one(&input.trim()), Some(1120));
+    }
+    #[test]
+    fn test_part_two() {
+        let input = aoc::read_file("test_inputs", 14);
+        assert_eq!(part_two(&input.trim()), None);
+    }
+}