Make it more cursed lmao

src/day06.rs

@@ -1,4 +1,3 @@
-use std::collections::HashMap;
 use crate::Day;
 
 pub struct Day06(Vec<u8>);
@@ -18,34 +17,20 @@ impl Day for Day06 {
 }
 
 impl Day06 {
+
     fn do_hashmap_magic(&self, days: u64) -> u64 {
         let x = self.0.clone();
-        let mut hm = HashMap::<u8, u64>::new();
+        let mut w: [u64; 9] = [0, 0, 0, 0, 0, 0, 0, 0, 0];
         for z in x {
-            let e = hm.entry(z).or_insert(0);
-            *e += 1;
+            w[z as usize] += 1;
         }
         for _ in 0..days {
-            let mut to_add = 0;
-            for num in 0..=8 {
-                if num == 0 {
-                    to_add = *hm.get(&0).unwrap_or(&0);
-                } else {
-                    let entry = { *hm.get(&num).unwrap_or(&0) };
-                    let prev = hm.entry(num - 1).or_insert(0);
-                    *prev = entry;
-                }
-            }
-            {
-                let en = hm.entry(8).or_insert(0);
-                *en = to_add;
-            }
-            {
-                let en = hm.entry(6).or_insert(0);
-                *en += to_add;
-            }
+            w = Self::foo(w);
         }
-        hm.values().sum::<u64>()
+        w.iter().sum()
+    }
+    fn foo([a, b, c, d, e, f, g, h, i]: [u64; 9]) -> [u64; 9] {
+        [b, c, d, e, f, g, h + a, i, a]
     }
 }