2024: day 11. part 2. rust

Author: Tsovak

Cargo.toml

@@ -67,3 +67,35 @@ path = "src/2024/day07/2/main.rs"
 [[bin]]
 name = "aoc-2024-day8-1"
 path = "src/2024/day08/1/main.rs"
+
+[[bin]]
+name = "aoc-2024-day8-2"
+path = "src/2024/day08/2/main.rs"
+
+[[bin]]
+name = "aoc-2024-day9-1"
+path = "src/2024/day09/1/main.rs"
+
+[[bin]]
+name = "aoc-2024-day9-2"
+path = "src/2024/day09/2/main.rs"
+
+[[bin]]
+name = "aoc-2024-day10-1"
+path = "src/2024/day10/1/main.rs"
+
+[[bin]]
+name = "aoc-2024-day10-2"
+path = "src/2024/day10/2/main.rs"
+
+[[bin]]
+name = "aoc-2024-day11-1"
+path = "src/2024/day11/1/main.rs"
+
+[[bin]]
+name = "aoc-2024-day11-2"
+path = "src/2024/day11/2/main.rs"
+
+[[bin]]
+name = "aoc-2024-day12-1"
+path = "src/2024/day12/1/main.rs"

src/2024/day11/2/main.rs

@@ -0,0 +1,61 @@
+use std::collections::HashMap;
+use std::fs;
+use std::path::Path;
+
+fn read_numbers() -> Vec<u64> {
+    let current_file = Path::new(file!());
+    let current_dir = current_file
+        .parent()
+        .expect("Failed to get parent directory");
+    let file_path = current_dir.join("data.txt");
+
+    fs::read_to_string(file_path)
+        .expect("Failed to read file")
+        .split_whitespace()
+        .map(|num| num.parse().expect("Failed to parse number"))
+        .collect()
+}
+
+fn split(number: u64) -> Vec<u64> {
+    if number == 0 {
+        return vec![1];
+    }
+
+    let number_str = number.to_string();
+    if number_str.len() % 2 == 0 {
+        let half = number_str.len() / 2;
+        let first = number_str[..half].parse().unwrap();
+        let second = number_str[half..].parse().unwrap();
+        vec![first, second]
+    } else {
+        vec![number * 2024]
+    }
+}
+
+fn blinking(numbers: Vec<u64>, until: usize) -> usize {
+    let mut stones: HashMap<u64, usize> = HashMap::new();
+    for &n in &numbers {
+        *stones.entry(n).or_insert(0) += 1;
+    }
+
+    for _ in 0..until {
+        let mut new_stones: HashMap<u64, usize> = HashMap::new();
+
+        for (&n, &count) in stones.iter() {
+            for split_num in split(n) {
+                *new_stones.entry(split_num).or_insert(0) += count;
+            }
+        }
+
+        stones = new_stones;
+    }
+
+    stones.values().sum()
+}
+
+fn main() {
+    let numbers = read_numbers();
+    let result = blinking(numbers, 75);
+
+    println!("{}", result);
+}