From 5a0d54ccd33b1367a74a48145ca0557a076da10c Mon Sep 17 00:00:00 2001
From: totycro <totycro@unknown-horizons.org>
Date: Sat, 21 Apr 2012 18:18:50 +0200
Subject: =?UTF-8?q?Erste=20lauff=C3=A4hige=20Version=20vom=20ersten=20Teil?=
 =?UTF-8?q?=20von=20Aufgabe=203?=
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---
 AufgabeFFP3.hs | 71 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 71 insertions(+)
 create mode 100644 AufgabeFFP3.hs

(limited to 'AufgabeFFP3.hs')

diff --git a/AufgabeFFP3.hs b/AufgabeFFP3.hs
new file mode 100644
index 0000000..67519be
--- /dev/null
+++ b/AufgabeFFP3.hs
@@ -0,0 +1,71 @@
+module AufgabeFFP3
+where
+
+import Prelude hiding (filter)
+
+type Weight = Int
+type Value = Int
+type Item = (Weight, Value)
+type Items = [Item]
+
+type Load = [Item]
+
+type Loads = [Load]
+type LoadWghtVal = (Load, Weight, Value)
+type MaxWeight = Weight
+
+safeGet :: [Integer] -> Int -> Integer -- get element of list, default to 0
+safeGet l i
+	| i < length l = l !! i
+	| otherwise = 0
+
+toBin :: Integer -> [Integer] -- get binary representation of integer
+toBin 0 = []
+toBin i = [rem] ++ toBin quot
+	where ( quot, rem ) = quotRem i 2
+
+hasBit :: Integer -> Int -> Bool -- check if the binary representation of a number has the ith bit set
+hasBit num ith = (safeGet (toBin num) ith) == 1
+
+getChoice :: Items -> Int -> Items -- choose a subset determined by binary representation of l
+getChoice l i = concat ( map (choose l) [0..(length l)-1]  )
+	where
+	choose l pos 
+		| hasBit (fromIntegral i) pos = [ l !! pos ]
+		| otherwise = []
+
+generator:: Items -> Loads -- get all possible choices (2^n)
+generator l = map ( getChoice l ) [1..num]
+	where num = (2^(length l)) - 1
+
+transformer :: Loads -> [LoadWghtVal] -- calc sum of weight and value for all lists of items
+transformer l = map trans l
+
+trans :: Load -> LoadWghtVal -- worker of transformer
+trans load = (load, weight, value)
+	where 
+	weight = sum $ map fst load
+	value = sum $ map snd load
+
+getWeight :: LoadWghtVal -> Weight
+getWeight (_, w, _) = w
+
+getVal :: LoadWghtVal -> Value
+getVal (_, _, v) = v
+
+filter :: MaxWeight -> [LoadWghtVal] -> [LoadWghtVal] -- drop those with too much weight
+filter max l = [ x | x <- l, getWeight x <= max ]
+
+selector :: [LoadWghtVal] -> [LoadWghtVal] -- get those with max val
+selector l = [ x | x <- l, getVal x == max ]
+	where max = maximum $ map getVal l
+
+selector1 :: [LoadWghtVal] -> [LoadWghtVal] -- all with max val
+selector1 = selector
+
+selector2 :: [LoadWghtVal] -> [LoadWghtVal] -- get ones with min weight
+selector2 l = [ x | x <- best, getWeight x == min ]
+	where
+	min = minimum $ map getWeight best
+	best = selector l 
+
-- 
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