From 417c4ede04df4bdd1bda1ba8e43842401b66c4fa Mon Sep 17 00:00:00 2001
From: Arranun <karliosos65@googlemail.com>
Date: Mon, 16 Dec 2019 16:45:29 +0100
Subject: [PATCH] Day16: This should be faster ...

---
 day16.hs | 24 +++++++++++++++---------
 1 file changed, 15 insertions(+), 9 deletions(-)

diff --git a/day16.hs b/day16.hs
index a449179..50d8429 100644
--- a/day16.hs
+++ b/day16.hs
@@ -1,17 +1,12 @@
 import Data.Char
-import Debug.Trace as T
 
 main = do
     cont <- getContents
-    let content = (map digitToInt $ init cont)
-    let base = [0,1,0,-1]
-    let patter = drop 500 (map (getPatternForIndex base (length content)) [0..(length content)])
-    let input = drop 500 content
-    
-    let test1 = doSteps input patter 1
-    --putStrLn (show input)
+    let content = (drop 5977377 ( concat $ replicate 10000 (map digitToInt $ init cont) )) 
+    let test1 = doStepsP2 content 1 
+    putStrLn (show $ length content)
     --mapM putStrLn (map show patter)
-    putStrLn (show test1)
+    putStrLn (show $ test1)
 
 getPatternForIndex :: [Int] -> Int -> Int -> [Int]
 getPatternForIndex patter length index = drop (1 + index) $ take  (length +1) (cycle base)
@@ -31,3 +26,14 @@ doSteps :: [Int] -> [[Int]] -> Int -> [Int]
 doSteps xs patterns cnt 
         | cnt == 0 = xs
         | otherwise = doSteps (step xs patterns) patterns (cnt -1)
+
+
+stepP2 :: [Int] -> Int -> [Int] -> [Int]
+stepP2 xs sumIn acc
+        | sumIn == 0 = acc   
+        | sumIn > 0 = stepP2 (drop 1 xs) (sumIn - (head xs))  (acc ++ [mod sumIn 10]) 
+
+doStepsP2 :: [Int] -> Int ->[Int]
+doStepsP2 xs cnt 
+        | cnt == 0 = xs
+        | otherwise = doStepsP2 (stepP2 xs (sum(xs)) []) (cnt -1)