Fix combination bug with small inventories

src/Multiset.hs

@@ -18,9 +18,19 @@ powlistUpToN' n (x:xs)
 -- there is a (probably) faster SO answer that produces power lists of size
 -- exactly N, but that answer is harder to adapt
 powlistUpToN :: Int -> [a] -> [[a]]
-powlistUpToN n xs = 
+powlistUpToN n xs = concat $ drop (length xs-n) (subseqsBySize xs)
+  where
+    subseqsBySize [] = [[[]]]
+    subseqsBySize (y:ys) =
+        let next = subseqsBySize ys
+        in zipWith (++) ([]:next) (map (map (y:)) next ++ [[]])
+powlistUpToN'' :: Int -> [a] -> [[a]]
+powlistUpToN'' n xs = 
     let l = length xs
-    in if n > l then [] else concat $ drop (l-n) (subseqsBySize xs)
+--    in if n > l then [] else concat $ drop (l-n) (subseqsBySize xs)
+    in if n > l 
+        then concat $ subseqsBySize xs
+        else concat $ drop (l-n) (subseqsBySize xs)
   where
     subseqsBySize [] = [[[]]]
     subseqsBySize (y:ys) =