Initial data commit

Task/Pascal-matrix-generation/Haskell/pascal-matrix-generation-2.hs

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+import Control.Monad (join)
+import Data.Bifunctor (bimap)
+import Data.Ix (range)
+import Data.List.Split (chunksOf)
+import Data.Tuple (swap)
+
+---------------------- PASCAL MATRIX ---------------------
+
+pascalMatrix :: ((Int, Int) -> (Int, Int)) -> Int -> [Int]
+pascalMatrix f n =
+  bc . f
+    <$> range
+      ((0, 0), join bimap pred (n, n))
+
+-- Binomial coefficient
+bc :: (Int, Int) -> Int
+bc (n, k) =
+  foldr
+    (\x a -> quot (a * succ (n - x)) x)
+    1
+    [k, pred k .. 1]
+
+
+--------------------------- TEST -------------------------
+matrixSize = 5 :: Int
+
+main :: IO ()
+main =
+  mapM_
+    putStrLn
+    ( unlines
+        . ( \(s, xs) ->
+              s :
+              (show <$> chunksOf matrixSize xs)
+          )
+        <$> zip
+          ["Lower", "Upper", "Symmetric"]
+          ( pascalMatrix
+              <$> [ id, -- Lower
+                    swap, -- Upper
+                    \(a, b) -> (a + b, b) -- Symmetric
+                  ]
+              <*> [matrixSize]
+          )
+    )