From 4c0b08c857afb6f308e01c19e5df68b994617311 Mon Sep 17 00:00:00 2001
From: Akshay <nerdy@peppe.rs>
Date: Sat, 5 Dec 2020 11:18:34 +0530
Subject: tidy up

---
 aoc.cabal      |  2 +-
 execs/Day05.hs | 21 +++++++--------------
 2 files changed, 8 insertions(+), 15 deletions(-)

diff --git a/aoc.cabal b/aoc.cabal
index 7b25a88..a5be71d 100644
--- a/aoc.cabal
+++ b/aoc.cabal
@@ -42,6 +42,6 @@ executable Day04
 
 executable Day05
   main-is:             Day05.hs
-  build-depends:       base, parsec
+  build-depends:       base
   default-language:    Haskell2010
   hs-source-dirs:      execs
diff --git a/execs/Day05.hs b/execs/Day05.hs
index 4251cd6..c018203 100644
--- a/execs/Day05.hs
+++ b/execs/Day05.hs
@@ -1,23 +1,16 @@
 module Main where
 
-import           Text.ParserCombinators.Parsec
-import Data.List (sort)
-import Control.Monad
-
 data Direction = Upper | Lower
 
-doHalving :: [Direction] -> (Int, Int) -> (Int, Int)
-doHalving [] p = p
-doHalving (Lower:rest) (l, u) = doHalving rest (l, (u+l) `div` 2)
-doHalving (Upper:rest) (l, u) = doHalving rest ((u+l) `div` 2 + 1, u)
-
-findId :: (Int, Int) -> Int
-findId (row, col) = row * 8 + col
+doHalf :: [Direction] -> (Int, Int) -> Int
+doHalf ls start = fst $ foldl fn start ls 
+    where fn (l, u) Lower = (l, (u+l) `div` 2)
+          fn (l, u) Upper = ((u+l) `div` 2 + 1, u)
 
 doValidate :: String -> Int
-doValidate s = findId (row, col)
-    where row = fst $ flip doHalving (0, 127) $ map readDir (take 7 s)
-          col = fst $ flip doHalving (0, 7) $ map readDir (drop 7 s)
+doValidate s = row * 8 + col
+    where row = flip doHalf (0, 127) $ map readDir (take 7 s)
+          col = flip doHalf (0, 7) $ map readDir (drop 7 s)
 
 readDir :: Char -> Direction
 readDir c
-- 
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