day 6: nonrecursive solution

1 files changed, 10 insertions, 7 deletions

diff --git a/6.py b/6.py
index b290710..2d189de 100644
--- a/6.py
+++ b/6.py
@@ -1,12 +1,15 @@
-from functools import cache
+from collections import Counter, deque
 from utils import open_day
 
 fish = list(map(int, open_day(6).read().split(',')))
 
-@cache
-def count_fish(life):
-    if life < 0: return 1
-    return count_fish(life - 7) + count_fish(life - 9)
+def solve(fish, life):
+    d = deque(Counter(fish)[i] for i in range(9))
+    for i in range(life):
+        zeros = d.popleft()
+        d[6] += zeros
+        d.append(zeros)
+    return sum(d)
 
-print(sum(count_fish(79 - f) for f in fish))
-print(sum(count_fish(255 - f) for f in fish))
+print(solve(fish, 80))
+print(solve(fish, 256))