Complete day 11 part 1

diff --git a/src/day11.rs b/src/day11.rs
new file mode 100644 (file)
index 0000000..d63dcf1
--- /dev/null
+++ b/src/day11.rs
@@ -0,0 +1,82 @@
+fn input() -> &'static str {
+    include_str!("../input/day11.txt")
+}
+
+fn parse(input: &str) -> Vec<u64> {
+    input
+        .split_whitespace()
+        .map(|s| s.parse().unwrap())
+        .collect()
+}
+
+fn iterate(stones: &[u64]) -> Vec<u64> {
+    stones
+        .iter()
+        .flat_map(|n| {
+            if *n == 0 {
+                vec![1]
+            } else {
+                let s = format!("{}", n);
+                let l = s.len();
+                if l % 2 == 0 {
+                    vec![s[0..l / 2].parse().unwrap(), s[l / 2..l].parse().unwrap()]
+                } else {
+                    vec![n * 2024]
+                }
+            }
+        })
+        .collect()
+}
+
+pub fn part1() {
+    let n = std::iter::successors(Some(parse(input())), |v| Some(iterate(v)))
+        .take(26)
+        .last()
+        .unwrap()
+        .len();
+    println!("Day 11 Part 1: {}", n);
+}
+
+pub fn part2() {
+    // lol no
+    let n = std::iter::successors(Some(parse(input())), |v| Some(iterate(v)))
+        .take(76)
+        .last()
+        .unwrap()
+        .len();
+    println!("Day 11 Part 2: {}", n);
+}
+
+#[cfg(test)]
+mod test {
+    use super::*;
+
+    const INPUT_STR: &str = concat!("0 1 10 99 999\n");
+
+    #[test]
+    fn test_parse() {
+        assert_eq!(parse(INPUT_STR), [0, 1, 10, 99, 999])
+    }
+
+    #[test]
+    fn test_iterate() {
+        assert_eq!(iterate(&parse(INPUT_STR)), [1, 2024, 1, 0, 9, 9, 2021976]);
+        assert_eq!(
+            std::iter::successors(Some(parse("125 17")), |v| Some(iterate(v)))
+                .take(7)
+                .collect::<Vec<_>>(),
+            [
+                vec![125, 17],
+                vec![253000, 1, 7],
+                vec![253, 0, 2024, 14168],
+                vec![512072, 1, 20, 24, 28676032],
+                vec![512, 72, 2024, 2, 0, 2, 4, 2867, 6032],
+                vec![1036288, 7, 2, 20, 24, 4048, 1, 4048, 8096, 28, 67, 60, 32],
+                vec![
+                    2097446912, 14168, 4048, 2, 0, 2, 4, 40, 48, 2024, 40, 48, 80, 96, 2, 8, 6, 7,
+                    6, 0, 3, 2
+                ]
+            ]
+        )
+    }
+}

diff --git a/src/main.rs b/src/main.rs
index f4353754473ae8ef7729f59be667ba92b90a5936..1e16e0df0862a0c589894362808f4a4ba76723e5 100644 (file)
--- a/src/main.rs
+++ b/src/main.rs
@@ -8,7 +8,7 @@ pub mod day07;
 pub mod day08;
 pub mod day09;
 pub mod day10;
-// pub mod day11;
+pub mod day11;
 // pub mod day12;
 // pub mod day13;
 // pub mod day14;
@@ -37,7 +37,7 @@ const DAYS: &[(Part, Part)] = &[
     (day08::part1 as fn(), day08::part2 as fn()),
     (day09::part1 as fn(), day09::part2 as fn()),
     (day10::part1 as fn(), day10::part2 as fn()),
-    // (day11::part1 as fn(), day11::part2 as fn()),
+    (day11::part1 as fn(), day11::part2 as fn()),
     // (day12::part1 as fn(), day12::part2 as fn()),
     // (day13::part1 as fn(), day13::part2 as fn()),
     // (day14::part1 as fn(), day14::part2 as fn()),