From d802e287f5f6cc95bc77023ee73031633e1b6ba0 Mon Sep 17 00:00:00 2001
From: chirvasitua <stuart-little@users.noreply.github.com>
Date: Wed, 20 Jan 2021 15:38:49 -0500
Subject: 1st commit on 086_haskell

---
 challenge-086/stuart-little/haskell/ch-1.hs |  9 +++++
 challenge-086/stuart-little/haskell/ch-2.hs | 56 +++++++++++++++++++++++++++++
 2 files changed, 65 insertions(+)
 create mode 100755 challenge-086/stuart-little/haskell/ch-1.hs
 create mode 100755 challenge-086/stuart-little/haskell/ch-2.hs

diff --git a/challenge-086/stuart-little/haskell/ch-1.hs b/challenge-086/stuart-little/haskell/ch-1.hs
new file mode 100755
index 0000000000..3b87974f9a
--- /dev/null
+++ b/challenge-086/stuart-little/haskell/ch-1.hs
@@ -0,0 +1,9 @@
+#!/usr/bin/env runghc
+
+-- run <script> <target number> <space-separated array entries>
+
+import System.Environment (getArgs,)
+
+main = do
+  (df:nrs) <- getArgs >>= return.(map (read::String->Int))
+  print $ elem df $ (map (\x->(x-)) nrs) <*> nrs
diff --git a/challenge-086/stuart-little/haskell/ch-2.hs b/challenge-086/stuart-little/haskell/ch-2.hs
new file mode 100755
index 0000000000..3288ece694
--- /dev/null
+++ b/challenge-086/stuart-little/haskell/ch-2.hs
@@ -0,0 +1,56 @@
+#!/usr/bin/env runghc
+
+-- run <script>
+
+import Data.List ((\\),group,)
+import Data.Matrix (Matrix,submatrix,mapPos,fromLists,toList,getRow,getCol,prettyMatrix,)
+import qualified Data.Vector as V (toList,)
+
+bdsMod3 :: Int -> (Int,Int)
+bdsMod3 i = (p,p+2) where
+  p = 3*(div (i-1) 3) + 1
+
+block33List :: (Int,Int) -> Matrix a -> [a]
+block33List (i,j) = toList . (submatrix lowi highi lowj highj) where
+  (lowi,highi) = bdsMod3 i
+  (lowj,highj) = bdsMod3 j
+
+rowToList :: Int -> Matrix a -> [a]
+rowToList i = V.toList . (getRow i)
+
+colToList :: Int -> Matrix a -> [a]
+colToList j = V.toList . (getCol j)
+
+possAtPos :: Eq a => [a] -> (Int,Int) -> Matrix a -> [a]
+possAtPos alph (i,j) mat = alph \\ (concat [(block33List (i,j) mat),(rowToList i mat),(colToList j mat)])
+
+nextPoss :: Eq a => [a] -> Matrix a -> Matrix [a]
+nextPoss alph mat = mapPos (\(i,j) a -> possAtPos alph (i,j) mat) mat
+
+iter1 :: Eq a => [a] -> Matrix a -> Matrix a
+iter1 alph mat = mapPos (
+  \pos a -> let possibilities = possAtPos alph pos mat in
+    if (notElem a alph) && (length possibilities == 1)
+            then (head possibilities)
+            else a
+  ) mat
+
+alph :: String
+alph = ['1'..'9']
+
+puzzle :: Matrix Char
+puzzle = fromLists [
+  "___26_7_1",
+  "68__7__9_",
+  "19___45__",
+  "82_1___4_",
+  "__46_29__",
+  "_5___3_28",
+  "__93___74",
+  "_4__5__36",
+  "7_3_18___"
+  ]
+
+main = do
+  let iterations = iterate (iter1 alph) puzzle
+  print $ (fst . head) $ dropWhile (\(x,y) -> x /= y) $ zip iterations $ tail iterations
-- 
cgit