Data commit

Task/Knapsack-problem-Continuous/Haskell/knapsack-problem-continuous-1.hs

@@ -0,0 +1,49 @@
+import Data.List (sortBy)
+import Data.Ord (comparing)
+import Text.Printf (printf)
+import Control.Monad (forM_)
+import Data.Ratio (numerator, denominator)
+
+maxWgt :: Rational
+maxWgt = 15
+
+data Bounty = Bounty
+  { itemName :: String
+  , itemVal, itemWgt :: Rational
+  }
+
+items :: [Bounty]
+items =
+  [ Bounty "beef" 36 3.8
+  , Bounty "pork" 43 5.4
+  , Bounty "ham" 90 3.6
+  , Bounty "greaves" 45 2.4
+  , Bounty "flitch" 30 4.0
+  , Bounty "brawn" 56 2.5
+  , Bounty "welt" 67 3.7
+  , Bounty "salami" 95 3.0
+  , Bounty "sausage" 98 5.9
+  ]
+
+solution :: [(Rational, Bounty)]
+solution = g maxWgt $ sortBy (flip $ comparing f) items
+  where
+    g room (b@(Bounty _ _ w):bs) =
+      if w < room
+        then (w, b) : g (room - w) bs
+        else [(room, b)]
+    f (Bounty _ v w) = v / w
+
+main :: IO ()
+main = do
+  forM_ solution $ \(w, b) -> printf "%s kg of %s\n" (mixedNum w) (itemName b)
+  (printf "Total value: %s\n" . mixedNum . sum) $ f <$> solution
+  where
+    f (w, Bounty _ v wtot) = v * (w / wtot)
+    mixedNum q =
+      if b == 0
+        then show a
+        else printf "%d %d/%d" a (numerator b) (denominator b)
+      where
+        a = floor q
+        b = q - toEnum a

Task/Knapsack-problem-Continuous/Haskell/knapsack-problem-continuous-2.hs

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+import Data.List (sortBy)
+import Data.Ord (comparing)
+import Text.Printf (printf)
+
+-- (name, (value, weight))
+items =
+  [ ("beef", (36, 3.8))
+  , ("pork", (43, 5.4))
+  , ("ham", (90, 3.6))
+  , ("greaves", (45, 2.4))
+  , ("flitch", (30, 4.0))
+  , ("brawn", (56, 2.5))
+  , ("welt", (67, 3.7))
+  , ("salami", (95, 3.0))
+  , ("sausage", (98, 5.9))
+  ]
+
+unitWeight (_, (val, weight)) = fromIntegral val / weight
+
+solution k = loop k . sortBy (flip $ comparing unitWeight)
+  where
+    loop k ((name, (_, weight)):xs)
+      | weight < k = putStrLn ("Take all the " ++ name) >> loop (k - weight) xs
+      | otherwise = printf "Take %.2f kg of the %s\n" (k :: Float) name
+
+main = solution 15 items