Data commit

Task/Equilibrium-index/Haskell/equilibrium-index-1.hs

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+import System.Random (randomRIO)
+import Data.List (findIndices, takeWhile)
+import Control.Monad (replicateM)
+import Control.Arrow ((&&&))
+
+equilibr xs =
+  findIndices (\(a, b) -> sum a == sum b) . takeWhile (not . null . snd) $
+  flip ((&&&) <$> take <*> (drop . pred)) xs <$> [1 ..]
+
+langeSliert = replicateM 2000 (randomRIO (-15, 15) :: IO Int) >>= print . equilibr

Task/Equilibrium-index/Haskell/equilibrium-index-2.hs

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+*Main> equilibr [-7, 1, 5, 2, -4, 3, 0]
+[3,6]

Task/Equilibrium-index/Haskell/equilibrium-index-3.hs

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+*Main> langeSliert
+[231,245,259,265,382,1480,1611,1612]

Task/Equilibrium-index/Haskell/equilibrium-index-4.hs

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+equilibriumIndices :: [Int] -> [Int]
+equilibriumIndices xs =
+  zip3
+    (scanl1 (+) xs) -- Sums from the left
+    (scanr1 (+) xs) -- Sums from the right
+    [0 ..] -- Indices
+    >>= (\(x, y, i) -> [i | x == y])
+
+--------------------------- TEST -------------------------
+main :: IO ()
+main =
+  mapM_
+    print
+    $ equilibriumIndices
+      <$> [ [-7, 1, 5, 2, -4, 3, 0],
+            [2, 4, 6],
+            [2, 9, 2],
+            [1, -1, 1, -1, 1, -1, 1],
+            [1],
+            []
+          ]