Fixed a bug that isn't a bug in practice

[advent-of-code-17.git] / src / advent15 / advent15.hs

diff --git a/src/advent15/advent15.hs b/src/advent15/advent15.hs
index 6ee03c04cf0c6a6b53cefd98d10cc954cd772c3a..4b16e08254898e636cc7b8befd6da560c4f56189 100644 (file)
--- a/src/advent15/advent15.hs
+++ b/src/advent15/advent15.hs
@@ -13,8 +13,8 @@ part1 = length $ filter (uncurry (==)) $ take 40000000 $ zip streamA streamB
 
 
 part2 = length $ filter (uncurry (==)) $ take 5000000 $ zip fsA fsB
-    where fsA = filteredStream 3 streamA
-          fsB = filteredStream 7 streamB
+    where fsA = stream' 4 generatorA generatorAStart -- filteredStream 3 streamA
+          fsB = stream' 8 generatorB generatorBStart -- filteredStream 7 streamB
 
 
 generatorA = generator 2147483647 16807
@@ -23,14 +23,19 @@ generatorB = generator 2147483647 48271
 streamA = stream generatorA generatorAStart
 streamB = stream generatorB generatorBStart
 
-generator :: Word64 -> Word64 -> Word64 -> Word64
+generator :: Int -> Int -> Int -> Int
 generator divisor factor n = n * factor `rem` divisor
 
-toWord16 :: Word64 -> Word16
+toWord16 :: Int -> Word16
 toWord16 = fromIntegral
 
-stream :: (Word64 -> Word64) -> Word64 -> [Word16]
+stream :: (Int -> Int) -> Int -> [Word16]
 stream gen n0 = map toWord16 $ drop 1 $ iterate gen n0
 
-filteredStream :: Word16 -> [Word16] -> [Word16]
-filteredStream f str = filter ((== 0) . ( .&. f)) str
+stream' :: Int -> (Int -> Int) -> Int -> [Word16]
+stream' f gen n0 = map toWord16 $ filter ((== 0) . (`mod` f)) $ drop 1 $ iterate gen n0
+
+
+-- filteredStream :: Word16 -> [Word16] -> [Word16]
+-- filteredStream f = filter ((== 0) . ( .&. f))
+