src/3n+1/Main.hs

@@ -1,47 +0,0 @@
-import           Control.Monad ()
-import           Debug.Trace   (trace)
-
-f' :: Integer -> Integer
-f' n = f'' 0 n
-  where
-    f'' :: Integer -> Integer -> Integer
-    f'' i n'
-      | n' == 1 = t' i
-      | even n' = t $ f'' (i + 1) (n' `div` 2)
-      | odd  n' = t $ f'' (i + 1) (3*n' + 1)
-      where t   = trace ("i: " ++ show i ++ ", number: " ++ show n')
-            t'  = t'' $ trace ("END: " ++ show n ++ ", length: " <> show i) $ t''
-            t'' = trace "\n#######################################################\n"
-
-f :: Integer -> Integer
-f n = s 0 n
-  where
-    s :: Integer -> Integer -> Integer
-    s i n
-      | n == 1 = i
-      | even n = s i' (n `div` 2)
-      | odd  n = s i' (3*n + 1)
-      where i' = i + 1
-
-main :: IO ()
-main = print $ map f [2^361..]
-
--- collatz collect
--- generate the collatz sequence and return it
-
-cc :: Integer -> [Integer]
-cc n = cc' [] n
-  where
-    cc' :: [Integer] -> Integer -> [Integer]
-    cc' acc n
-      | n == 1 = 1:acc
-      | even n = cc' acc' (n `div` 2)
-      | odd  n = cc' acc' (3*n + 1)
-      where acc' = acc <> [n]
-
-primes :: [Integer]
-primes = sieve [2..]
-  where
-    sieve (p:xs) = p : sieve [x|x <- xs, x `mod` p > 0]
-
-isPrime k = (k > 1) && null [ x | x <- [2..k - 1], k `mod` x == 0]

src/projectEuler/question1.hs

@@ -13,9 +13,6 @@ main = print ans
 ans :: Integer
 ans = sum $ allNumbersUnder 1000
 
-sum' :: Num a => [a] -> a
-sum' = foldl (+) 0
-
 isMultipleOf :: Integral a => a -> a -> Bool
 isMultipleOf n x = x `rem` n == 0
 

src/projectEuler/question15.hs

@@ -14,31 +14,10 @@ main = print ans
 
 ans = 42
 
-limit = 2
-points = [ (x,y)
-  | x <- [0..limit]
-  , y <- [0..limit]
-  ]
+limit = 20
+points = [(x,y) | x <- [1..limit], y <- [1..limit]]
 
 data Direction = Right | Down
 
 move Right (x,y) = (x+1, y  )
 move Down  (x,y) = (x  , y+1)
-
--- solve :: (Int, Int) -> [[(Int, Int)]]
-{-
-λ> [(0,0)]
-[(0,0)]
-λ> [(0,0),(1,0),(2,0),(2,1),(2,2)]
-[(0,0),(1,0),(2,0),(2,1),(2,2)]
-λ> [ [(0,0),(1,0),(2,0),(2,1),(2,2)], [(0,0),(1,0),(1,1),(2,1),(2,2)]]
-[[(0,0),(1,0),(2,0),(2,1),(2,2)],[(0,0),(1,0),(1,1),(2,1),(2,2)]]
-λ>
--}
-
-data Tree a
-  = Leaf a
-  | Branch (Tree a) (Tree a)
-  deriving (Show)
-
-

src/projectEuler/question16.hs

@@ -1,15 +0,0 @@
-{-
-https://projecteuler.net/problem=16
-
-2^15 = 32768 and the sum of its digits is 3 + 2 + 7 + 6 + 8 = 26.
-
-What is the sum of the digits of the number 2^1000?
--}
-
-module Main where
-
-main :: IO ()
-main = print ans
-
-ans :: Integer
-ans = sum $ map (\c -> read [c] :: Integer) $ show (2^1000)