From 6ca4b02c6761fc56984489896a3e7cb0a74a3941 Mon Sep 17 00:00:00 2001
From: Bill Ewanick <bill@ewanick.com>
Date: Mon, 27 Nov 2023 16:14:16 -0500
Subject: [PATCH] Start of magic square

---
 src/hackerRank/algorithms-magicSquare.hs | 37 ++++++++++++++++++++++++
 1 file changed, 37 insertions(+)
 create mode 100644 src/hackerRank/algorithms-magicSquare.hs

diff --git a/src/hackerRank/algorithms-magicSquare.hs b/src/hackerRank/algorithms-magicSquare.hs
new file mode 100644
index 0000000..5d0fa37
--- /dev/null
+++ b/src/hackerRank/algorithms-magicSquare.hs
@@ -0,0 +1,37 @@
+-- https://www.hackerrank.com/challenges/magic-square-forming/problem
+
+module Main where
+import           Data.List (transpose)
+
+main :: IO ()
+main = print "test"
+
+s :: [[Integer]]
+s =
+  [ [5, 3, 4]
+  , [1, 5, 8]
+  , [6, 4, 2]
+  ]
+
+-- isMagicSquare n s =
+--   all (sum rows == n) &&
+--   all (sum cols == n) &&
+--   all (sum diag == n)
+--   where
+--     rows =
+
+get s (x,y) = s !! x !! y
+
+allCoords n = [ (x,y) | x <- [0..n-1], y <- [0..n-1] ]
+
+diagCoords n = [ (x,y) | x <- [0..n-1], y <- [0       ..n-1], x == y       ] ++
+               [ (x,y) | x <- [0..n-1], y <- [n-1, n-2..  0], x + y == n-1 ]
+
+rowSums :: [[Integer]] -> [Integer]
+rowSums = map sum
+
+colSums :: [[Integer]] -> [Integer]
+colSums = map sum . transpose
+
+diagSums :: [[Integer]] -> [Integer]
+diagSums n = map (\(x,y) -> get n (x,y)) (diagCoords 3)