Solved day 11

Cargo.toml

@@ -25,6 +25,7 @@ test_lib = []
 chrono = { version = "0.4.38", optional = true }
 dhat = { version = "0.3.3", optional = true }
 itertools = "0.13.0"
+memoize = "0.4.2"
 pico-args = "0.5.0"
 regex = "1.11.1"
 tinyjson = "2.5.1"

README.md

@@ -41,6 +41,7 @@ algorithm to Rust, and *when I find the time*, optimising that algorithm in Rust
 | [Day 8](./src/bin/08.rs) | `-` | `-` |
 | [Day 9](./src/bin/09.rs) | `-` | `-` |
 | [Day 10](./src/bin/10.rs) | `547.0µs` | `432.9µs` |
+| [Day 11](./src/bin/11.rs) | `272.0ns` | `259.0ns` |
 
 **Total: 3538.78ms**
 <!--- benchmarking table --->

data/examples/11.txt

@@ -0,0 +1 @@
+125 17

src/bin/11.rs

@@ -0,0 +1,62 @@
+advent_of_code::solution!(11);
+use memoize::memoize;
+
+fn parse_input(input: &str) -> Vec<u64> {
+    input
+        .trim()
+        .split_whitespace()
+        .map(|s| s.parse().unwrap())
+        .collect()
+}
+
+// Memoization here does the heck of a job...
+#[memoize]
+fn blink(stone: u64, n_blinks: u32) -> u64 {
+    if n_blinks == 0 {
+        return 1;
+    }
+    if stone == 0 {
+        return blink(1, n_blinks - 1);
+    }
+
+    let digits = stone.ilog10() as u32 + 1;
+    if digits % 2 == 0 {
+        let left = stone / 10_u64.pow(digits / 2);
+        let right = stone % 10_u64.pow(digits / 2);
+        return blink(left, n_blinks - 1) + blink(right, n_blinks - 1);
+    }
+
+    return blink(stone * 2024, n_blinks - 1);
+}
+
+fn blinks(input: &str, times: u32) -> u64 {
+    let stones = parse_input(input);
+    stones.iter().map(|&stone| blink(stone, times)).sum()
+}
+
+pub fn part_one(input: &str) -> Option<u64> {
+    Some(blinks(input, 25))
+}
+
+pub fn part_two(input: &str) -> Option<u64> {
+    Some(blinks(input, 75))
+}
+
+#[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));
+    }
+}