.

2021/6.js

@@ -1,14 +1,11 @@
-function iterate(counts) {
-    return [counts[1], counts[2], counts[3], counts[4], counts[5], counts[6], counts[7] + counts[0], counts[8], counts[0]]
-}
-
 function day6(input, part2) {
     input = input.split(",").num()
 
     let counts = Array(9).fill().map((_, i) => input.count(i))
 
     for (let i = 0; i < (part2 ? 256 : 80); i++) {
-        counts = iterate(counts)
+        counts = counts.rotate(1)
+        counts[6] += counts[8]
     }
 
     return counts.sum()