more shit

src/Lib.hs

@@ -5,6 +5,8 @@ module Lib
   )
 where
 
+import Data.List
+
 someFunc :: IO ()
 someFunc = putStrLn "someFunc"
 
@@ -22,7 +24,6 @@ doubleList :: [Int] -> [Int]
 doubleList [] = []
 doubleList xs = mapList (* 2) xs
 
-
 -- | Replaces all occurrences of a char in a string with another char
 replace :: String -> Char -> Char -> String
 replace [] _ _ = []
@@ -38,7 +39,7 @@ replaceMultiple [] _ _ = []
 replaceMultiple [x] c r
   | x `elem` c = [r]
   | otherwise = [x]
-replaceMultiple (x:xs) c r
+replaceMultiple (x : xs) c r
   | x `elem` c = r : replaceMultiple xs c r
   | otherwise = x : replaceMultiple xs c r
 
@@ -55,8 +56,7 @@ getFactors x y
   | x `div` 2 < y = [x]
   | x `mod` y == 0 = y : getFactors x (y + 1)
   | otherwise = getFactors x (y + 1)
-  
+
-  
 -- Get all prime factors for a number
 primeFactor :: Int -> [Int]
 primeFactor n = getPrimeFactors n 2
@@ -66,4 +66,57 @@ getPrimeFactors :: Int -> Int -> [Int]
 getPrimeFactors n m
   | n `div` 2 < m = [n]
   | n `mod` m == 0 = m : getPrimeFactors (n `div` m) 2
-  | otherwise = getPrimeFactors n (m + 1)
+  | otherwise = getPrimeFactors n (m + 1)
+
+checksum :: Int -> Int
+checksum 0 = 0
+checksum n = (n `mod` 10) + checksum (n `div` 10)
+
+sumList :: [Int] -> Int
+sumList [] = 0
+sumList [x] = x
+sumList (x : xs) = x + sumList xs
+
+sumListF :: [Int] -> Int
+sumListF = foldl (+) 0
+
+{-
+'sumListF xs = foldl (\a n -> a + n) 0 xs' can be eta reduced to 'sumListF = foldl (\a n -> a + n) 0'
+why? due to currying, 'foldl (\a n -> a + n) 0' returns a function that is then applied to xs
+sp instead of applying a function to a value that just applies another function to that value, we can just let that
+outer function be the inner function directly
+
+the lambda expression '(\a n -> a + n)' can also be changed to (+)
+why? the lambda is a function that takes two inputs and adds them, exactly the same as (+)
+
+this can be further reduced to sum but like no
+-}
+
+fizzBuzz :: IO ()
+fizzBuzz = putStrLn $ intercalate "\n" [fizzBuzzSingle n | n <- [1..100]]
+
+fizzBuzzSingle :: Int -> String
+fizzBuzzSingle n
+  | n `mod` 15 == 0 = "FizzBuzz"
+  | n `mod` 5 == 0 = "Buzz"
+  | n `mod` 3 == 0 = "Fizz"
+  | otherwise = show n
+
+
+
+-- connect a string list so that it overlaps the strings
+-- ["hi", "india", "ares", "resolution"] -> "hindiaresolution"
+connectStrings :: [String] -> String
+connectStrings [] = []
+connectStrings [x] = x
+connectStrings (x : y : []) = ""
+connectStrings _ = "not implemented yet"
+
+connectStrings2 :: String -> String -> String
+connectStrings2 x y = []
+
+getCommonPart :: String -> String -> String
+getCommonPart [] _ = []
+getCommonPart x y
+  | x `isPrefixOf` y = x
+  | otherwise = getCommonPart (tail x) y