Data commit

Task/Department-numbers/Haskell/department-numbers-1.hs

@@ -0,0 +1,12 @@
+main :: IO ()
+main =
+  mapM_ print $
+  [2, 4, 6] >>=
+  \x ->
+     [1 .. 7] >>=
+     \y ->
+        [12 - (x + y)] >>=
+        \z ->
+           case y /= z && 1 <= z && z <= 7 of
+             True -> [(x, y, z)]
+             _ -> []

Task/Department-numbers/Haskell/department-numbers-2.hs

@@ -0,0 +1,9 @@
+main :: IO ()
+main =
+  mapM_
+    print
+    [ (x, y, z)
+    | x <- [2, 4, 6]
+    , y <- [1 .. 7]
+    , z <- [12 - (x + y)]
+    , y /= z && 1 <= z && z <= 7 ]

Task/Department-numbers/Haskell/department-numbers-3.hs

@@ -0,0 +1,9 @@
+main :: IO ()
+main =
+  mapM_ print $
+  do x <- [2, 4, 6]
+     y <- [1 .. 7]
+     z <- [12 - (x + y)]
+     if y /= z && 1 <= z && z <= 7
+       then [(x, y, z)]
+       else []

Task/Department-numbers/Haskell/department-numbers-4.hs

@@ -0,0 +1,14 @@
+import Data.List (nub)
+
+main :: IO ()
+main =
+  let xs = [1 .. 7]
+  in mapM_ print $
+     xs >>=
+     \x ->
+        xs >>=
+        \y ->
+           xs >>=
+           \z ->
+              [ (x, y, z)
+              | even x && 3 == length (nub [x, y, z]) && 12 == sum [x, y, z] ]

Task/Department-numbers/Haskell/department-numbers-5.hs

@@ -0,0 +1,28 @@
+-------------------- DEPARTMENT NUMBERS ------------------
+
+options :: Int -> Int -> Int -> [(Int, Int, Int)]
+options lo hi total =
+  ( \ds ->
+      filter even ds
+        >>= \x ->
+          filter (/= x) ds
+            >>= \y ->
+              [total - (x + y)]
+                >>= \z ->
+                  [ (x, y, z)
+                    | y /= z && lo <= z && z <= hi
+                  ]
+  )
+    [lo .. hi]
+
+--------------------------- TEST -------------------------
+main :: IO ()
+main =
+  let xs = options 1 7 12
+   in putStrLn "(Police, Sanitation, Fire)\n"
+        >> mapM_ print xs
+        >> mapM_
+          putStrLn
+          [ "\nNumber of options: ",
+            show (length xs)
+          ]

Task/Department-numbers/Haskell/department-numbers-6.hs

@@ -0,0 +1,8 @@
+options :: Int -> Int -> Int -> [(Int, Int, Int)]
+options lo hi total =
+  let ds = [lo .. hi]
+  in [ (x, y, z)
+     | x <- filter even ds
+     , y <- filter (/= x) ds
+     , let z = total - (x + y)
+     , y /= z && lo <= z && z <= hi ]

Task/Department-numbers/Haskell/department-numbers-7.hs

@@ -0,0 +1,10 @@
+import Control.Monad (guard)
+
+options :: Int -> Int -> Int -> [(Int, Int, Int)]
+options lo hi total =
+  let ds = [lo .. hi]
+  in do x <- filter even ds
+        y <- filter (/= x) ds
+        let z = total - (x + y)
+        guard $ y /= z && lo <= z && z <= hi
+        return (x, y, z)