1st commit on 125_haskell

2 files changed, 61 insertions, 0 deletions

diff --git a/challenge-125/stuart-little/haskell/ch-1.hs b/challenge-125/stuart-little/haskell/ch-1.hs
new file mode 100755
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+++ b/challenge-125/stuart-little/haskell/ch-1.hs
@@ -0,0 +1,13 @@
+#!/usr/bin/env runghc
+
+-- run <script> <number>
+
+import System.Environment (getArgs)
+
+trps :: Int -> [[Int]]
+trps n = top ++ mid where
+  top = filter (\[x,y,z] -> x>0 && y>0 && x^2+y^2==z^2) [[i,(floor $ sqrt $ fromIntegral (n^2-i^2)),n] | i <- [1..div (n+1) 2]]
+  mid = map (\i-> [div ((div (n^2) i)-i) 2, n, div ((div (n^2) i)+i) 2]) $ filter(\i-> mod (n^2) i == 0 && mod i 2 == mod (div (n^2) i) 2) [1..n-1]
+
+main :: IO ()
+main = getArgs >>= putStrLn . (\x-> if length x > 0 then x else "-1") . unlines . map unwords . (map.map) show . trps.(read::String->Int).head
diff --git a/challenge-125/stuart-little/haskell/ch-2.hs b/challenge-125/stuart-little/haskell/ch-2.hs
new file mode 100755
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+++ b/challenge-125/stuart-little/haskell/ch-2.hs
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+#!/usr/bin/env runghc
+
+import Data.List ((\\), inits)
+import Data.List.Extra (maximumOn)
+import System.Environment (getArgs)
+
+lr :: [String] -> [[String]]
+lr xs
+  |(length xs < 3) || (head xs == ".") =[[],[]]
+  |length xs == 3 =[["."],["."]]
+  |otherwise = [l, (tail xs) \\ l] where
+     l = head $ filter (((-1)==).sum.map (\x-> if x == "." then (-1) else 1)) $ inits $ tail xs
+
+lrLongPath :: [String] -> [[String]]
+lrLongPath xs
+  |head xs == "." =[[],[]]
+  |length xs == 3 = replicate 2 [head xs]
+  |otherwise = map ((head xs):) $ map ((maximumOn length).lrLongPath) $ lr xs     
+
+biLongPath :: [String] -> [String]
+biLongPath xs
+  |length xs < 3 || head xs == "." =[]
+  |length xs == 3 = [head xs]
+  |otherwise = maximumOn length [path, biLongPath(left), biLongPath(right)] where
+     [left,right] = lr(xs)
+     [lPath,rPath] = lrLongPath(xs)
+     path = (reverse $ tail lPath) ++ rPath
+
+main :: IO ()
+main = getArgs >>= putStrLn.unwords.biLongPath
+
+{-
+run <script> <tree in preorder form with '.' for empty nodes, entered as space-separated values>
+
+ref: https://stackoverflow.com/a/2676849/11064961
+
+e.g. 1 2 4 . 7 . . . 3 5 . . 6 . . represents the tree
+
+        1
+       / \
+      2   3
+     /   / \
+    4   5   6
+     \
+      7
+
+given as an example in the problem formulation at https://perlweeklychallenge.org/blog/perl-weekly-challenge-113/#TASK2
+-}