From 2d02f553aa4cc4ded630628eccdf34f55937cee5 Mon Sep 17 00:00:00 2001
From: tomsmeding <tom.smeding@gmail.com>
Date: Wed, 14 Dec 2016 20:19:02 +0100
Subject: Add 2015 sources

---
 2015/day13.hs | 47 +++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 47 insertions(+)
 create mode 100644 2015/day13.hs

(limited to '2015/day13.hs')

diff --git a/2015/day13.hs b/2015/day13.hs
new file mode 100644
index 0000000..6ffc440
--- /dev/null
+++ b/2015/day13.hs
@@ -0,0 +1,47 @@
+import Data.Maybe
+import Control.Monad
+import qualified Data.Map.Strict as Map
+import Data.Map.Strict ((!))
+
+includeSelf :: Bool
+includeSelf = True
+
+getnames :: [String] -> Map.Map String Int
+getnames [] = Map.empty
+getnames (l:ls) = Map.insert (head (words l)) (Map.size n) n
+    where n = getnames ls
+
+parse :: [String] -> Map.Map String Int -> Map.Map (Int,Int) Int
+parse [] names = Map.empty
+parse (l:ls) names = Map.insert (a,b) h $ parse ls names
+    where w = words l
+          an = head w
+          bn = init $ last w
+          a = names ! an
+          b = names ! bn
+          neg = w!!2 == "lose"
+          hp = read $ w!!3
+          h = if neg then -hp else hp
+
+permutations :: [a] -> [[a]]
+permutations [] = []
+permutations [v] = [[v]]
+permutations a = concat [map ((a!!i):) $ permutations $ take i a ++ drop (i + 1) a | i <- [0..(length a - 1)]]
+
+compute :: [Int] -> Map.Map (Int,Int) Int -> Int
+compute [] _ = 0
+compute [_] _ = 0
+compute l hm = fst $ foldl (\(acc,prev) i -> (acc + hm ! (prev,i) + hm ! (i,prev),i)) (0,last l) l
+
+addSelf :: Int -> Map.Map (Int,Int) Int -> Map.Map (Int,Int) Int
+addSelf n m = foldl (\mp i -> Map.insert (0,i) 0 $ Map.insert (i,0) 0 mp) m [1..n]
+
+day13 :: IO ()
+day13 = do
+    input <- liftM lines $ readFile "day13.txt"
+    let names = getnames input
+    let hapmap = if includeSelf then addSelf (length names) parsed else parsed where parsed = parse input names
+    let perm = permutations [(if includeSelf then 0 else 1)..(length names)]
+    print $ maximum [compute p hapmap | p <- perm]
+
+main = day13
-- 
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