Solved day 11

input/day11.txt

@@ -0,0 +1 @@
+6563348 67 395 0 6 4425 89567 739318

src/day11.rs

@@ -0,0 +1,78 @@
+use std::collections::HashMap;
+use num::Integer;
+use crate::day_solver::DaySolver;
+#[cfg(test)]
+use crate::util::read_file;
+
+pub struct Day11 {
+    pebbles: Vec<u64>
+}
+
+impl Day11 {
+
+    pub fn create(input: String) -> Self {
+        Day11 {
+            pebbles: input.split_whitespace().filter_map(|n| n.parse::<u64>().ok()).collect()
+        }
+    }
+
+    fn split_digits(n: u64) -> (u64, u64) {
+        let digits = n.ilog10() + 1;
+        assert!(digits.is_even());
+        let factor = 10u64.pow(digits / 2);
+        (n / factor, n % factor)
+    }
+
+    fn count_pebbles_after_blinks(pebble: u64, blinks: usize, cache: &mut HashMap<(u64, usize), u64>) -> u64 {
+        if blinks == 0 { return 1 };
+        let cache_key = (pebble, blinks);
+        if let Some(cached) = cache.get(&cache_key) {
+            return cached.to_owned();
+        }
+
+        let res = if pebble == 0 {
+            Self::count_pebbles_after_blinks(1, blinks - 1, cache)
+        } else if pebble.ilog10().is_odd() {
+            let (left, right) = Self::split_digits(pebble.to_owned());
+            Self::count_pebbles_after_blinks(left, blinks - 1, cache) + Self::count_pebbles_after_blinks(right, blinks - 1, cache)
+        } else {
+            Self::count_pebbles_after_blinks(pebble * 2024, blinks - 1, cache)
+        };
+
+        cache.insert(cache_key, res);
+        res
+    }
+
+    fn count_total_pebbles_after_blinks(pebbles: &[u64], blinks: usize) -> u64 {
+        pebbles.iter().map(|p| Self::count_pebbles_after_blinks(p.to_owned(), blinks, &mut HashMap::new())).sum::<u64>()
+    }
+}
+
+impl DaySolver for Day11 {
+
+
+    fn solve_part1(&mut self) -> String {
+        Self::count_total_pebbles_after_blinks(&self.pebbles.clone(), 25).to_string()
+    }
+
+    fn solve_part2(&mut self) -> String {
+        Self::count_total_pebbles_after_blinks(&self.pebbles.clone(), 75).to_string()
+    }
+}
+
+#[test]
+fn test_part1_basic() {
+    assert_eq!(7, Day11::count_total_pebbles_after_blinks(&vec![0, 1, 10, 99, 999], 1));
+}
+
+#[test]
+fn test_part1() {
+    let mut day = Day11::create("125 17".into());
+    assert_eq!("55312", day.solve_part1());
+}
+
+#[test]
+fn test_part2() {
+    let mut day = Day11::create(read_file("input/day11_example.txt"));
+    assert_eq!("EXAMPLE_ANSWER", day.solve_part2());
+}

src/main.rs

@@ -2,6 +2,7 @@ extern crate core;
 
 use std::time::Instant;
 use crate::day10::Day10;
+use crate::day11::Day11;
 use crate::day1::Day1;
 use crate::day2::Day2;
 use crate::day3::Day3;
@@ -26,6 +27,7 @@ mod day7;
 mod day8;
 mod day9;
 mod day10;
+mod day11;
 
 const DEFAULT_BENCHMARK_AMOUNT: u32 = 100;
 
@@ -107,7 +109,7 @@ fn build_day_solver(day: u8, input: String) -> Option<Box<dyn DaySolver>> {
         8 => Some(Box::new(Day8::create(input))),
         9 => Some(Box::new(Day9::create(input))),
         10 => Some(Box::new(Day10::create(input))),
-        // 11 => Some(Box::new(Day11::create(input))),
+        11 => Some(Box::new(Day11::create(input))),
         // 12 => Some(Box::new(Day12::create(input))),
         _ => None
     }