11th day

Author: majcn

data/examples/11.txt

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+125 17

src/bin/11.rs

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+advent_of_code::solution!(11);
+
+use advent_of_code::majcn::math::*;
+use advent_of_code::maneatingape::hash::*;
+use advent_of_code::maneatingape::parse::*;
+
+fn parse_data(input: &str) -> Vec<u32> {
+    input.iter_unsigned().collect()
+}
+
+fn calculate_step(v: u64) -> [Option<u64>; 2] {
+    if v == 0 {
+        return [Some(1), None];
+    }
+
+    let n = v.count_digits() as u32;
+    if n % 2 == 0 {
+        let split_value = 10_u64.pow(n / 2);
+        return [Some(v / split_value), Some(v % split_value)];
+    }
+
+    [Some(v * 2024), None]
+}
+
+fn calculate<const N: usize>(v: u64, i: usize, cache: &mut FastMap<(usize, u64), u64>) -> u64 {
+    if i == N {
+        return 1;
+    }
+
+    if let Some(cached_result) = cache.get(&(i, v)) {
+        return *cached_result;
+    }
+
+    let result = calculate_step(v)
+        .into_iter()
+        .filter_map(|x| Some(calculate::<N>(x?, i + 1, cache)))
+        .sum();
+
+    cache.insert((i, v), result);
+
+    result
+}
+
+fn part_x<const N: usize>(data: Vec<u32>) -> u64 {
+    let mut cache = FastMap::new();
+
+    data.into_iter()
+        .map(|x| calculate::<N>(x as u64, 0, &mut cache))
+        .sum()
+}
+
+pub fn part_one(input: &str) -> Option<u64> {
+    let data = parse_data(input);
+
+    let result = part_x::<25>(data);
+
+    Some(result)
+}
+
+pub fn part_two(input: &str) -> Option<u64> {
+    let data = parse_data(input);
+
+    let result = part_x::<75>(data);
+
+    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(55312));
+    }
+
+    #[test]
+    fn test_part_two() {
+        let result = part_two(&advent_of_code::template::read_file("examples", DAY));
+        assert_eq!(result, Some(65601038650482));
+    }
+}