Day 14 part 2.

src/day14.rs

@@ -29,7 +29,38 @@ fn part1(input: &Vec<(usize, usize, usize)>) -> usize {
         .unwrap()
 }
 
-// #[aoc(day14, part2)]
+#[aoc(day14, part2)]
-// fn part2(input: &str) -> String {
+fn part2(input: &Vec<(usize, usize, usize)>) -> usize {
-//     todo!()
+    play(input, 2503)
-// }
+}
+
+fn play(input: &Vec<(usize, usize, usize)>, rounds: usize) -> usize {
+    let mut state = vec![(0usize, 0usize); input.len()];
+    for time in 1..=rounds {
+        for i in 0..input.len() {
+            let (speed, fly, rest) = input[i];
+            let rem = (time - 1) % (fly + rest);
+            let flying = rem < fly;
+            if flying {
+                state[i].0 += speed;
+            }
+        }
+
+        let max_distance = state.iter().map(|it| it.0).max().unwrap();
+        state.iter_mut().for_each(|it| if it.0 == max_distance {
+            it.1 += 1;
+        });
+    }
+    state.into_iter().map(|it| it.1).max().unwrap()
+}
+
+#[cfg(test)]
+mod test {
+    use crate::day14::{parse, play};
+
+    #[test]
+    fn example2() {
+        assert_eq!(689, play(&parse("Comet can fly 14 km/s for 10 seconds, but then must rest for 127 seconds.
+Dancer can fly 16 km/s for 11 seconds, but then must rest for 162 seconds."), 1000))
+    }
+}