much simpler

1 files changed, 1 insertions, 7 deletions

diff --git a/9.py b/9.py
index a98d67a..9edf082 100644
--- a/9.py
+++ b/9.py
@@ -10,13 +10,7 @@ def predict_next(history: list[int]) -> int:
     )
 
 
-def predict_prev(history: list[int]) -> int:
-    if all(e == 0 for e in history):
-        return 0
-    return history[0] - predict_prev([a - b for a, b in zip(history[1:], history[:-1])])
-
-
 histories = [[int(e) for e in l.rstrip().split()] for l in stdin]
 
 print(sum(predict_next(history) for history in histories))
-print(sum(predict_prev(history) for history in histories))
+print(sum(predict_next(history[::-1]) for history in histories))