d11

res/11/example

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

res/11/input

@@ -0,0 +1 @@
+814 1183689 0 1 766231 4091 93836 46

src/days/d11.rs

@@ -1,4 +1,4 @@
-use std::fs;
+use std::{collections::HashMap, fs};
 
 pub fn solve() {
     let path = "res/11/input";
@@ -6,11 +6,58 @@ pub fn solve() {
     #[allow(unused)]
     let contents = fs::read_to_string(path).expect("Something went wrong reading the file");
 
-    let result: usize = 0;
+    let mut map: HashMap<usize, usize> = HashMap::new();
+    contents
+        .trim()
+        .split(' ')
+        .map(|n| n.parse::<usize>().unwrap())
+        .for_each(|n| {
+            map.insert(n, 1);
+        });
+
+    for _ in 0..25 {
+        map = blink(map);
+    }
+
+    let result: usize = map.iter().map(|(_, v)| v).sum();
 
     println!("Result 1: {}", result);
 
-    let result: usize = 0;
+    for _ in 0..50 {
+        map = blink(map);
+    }
+
+    let result: usize = map.iter().map(|(_, v)| v).sum();
 
     println!("Result 2: {}", result);
 }
+
+fn blink(map: HashMap<usize, usize>) -> HashMap<usize, usize> {
+    let mut new_map: HashMap<usize, usize> = HashMap::new();
+    for (k, v) in map.iter() {
+        if *k == 0 {
+            *new_map.entry(1).or_insert(0) += *v;
+        } else if k.to_string().len() % 2 == 0 {
+            // split num into two halves
+            let n1 = k
+                .to_string()
+                .chars()
+                .take(k.to_string().len() / 2)
+                .collect::<String>()
+                .parse::<usize>()
+                .unwrap();
+            let n2 = k
+                .to_string()
+                .chars()
+                .skip(k.to_string().len() / 2)
+                .collect::<String>()
+                .parse::<usize>()
+                .unwrap();
+            *new_map.entry(n1).or_insert(0) += *v;
+            *new_map.entry(n2).or_insert(0) += *v;
+        } else {
+            *new_map.entry((*k) * 2024).or_insert(0) += *v;
+        }
+    }
+    new_map
+}