fix: nextguess was not implemented to account for duplicate notes/octaves

Proj2.hs

@@ -12,6 +12,7 @@ where
 
 import Data.List
 import Data.Set qualified as S
+import Debug.Trace
 
 -- datatypes --
 
@@ -69,20 +70,24 @@ toPitch _ = Nothing
 feedback :: [Pitch] -> [Pitch] -> (Int, Int, Int)
 feedback target guess = (length correctPitches, correctNotes, correctOctaves)
   where
+    -- since pitches are unique in a guess,
+    -- we can use set math to count how many are correct
     targetSet = S.fromList target
     guessSet = S.fromList guess
 
     correctPitches = S.intersection targetSet guessSet
-    newTarget = S.difference targetSet correctPitches
-    newGuess = S.difference guessSet correctPitches
 
-    targetNoteSet = S.map note newTarget
-    guessNoteSet = S.map note newGuess
-    targetOctaveSet = S.map octave newTarget
-    guessOctaveSet = S.map octave newGuess
+    newTarget = S.toList $ S.difference targetSet correctPitches
+    newGuess = S.toList $ S.difference guessSet correctPitches
 
-    correctNotes = length $ S.intersection targetNoteSet guessNoteSet
-    correctOctaves = length $ S.intersection targetOctaveSet guessOctaveSet
+    (targetNotes, guessNotes) = (map note newTarget, map note newGuess)
+    (targetOctaves, guessOctaves) = (map octave newTarget, map octave newGuess)
+
+    -- since notes and octaves are not unique in a guess,
+    -- we can compare the guess to all possible permutations of the target
+    -- and count the pairwise note/octave matches
+    correctNotes = matches targetNotes guessNotes
+    correctOctaves = matches targetOctaves guessOctaves
 
 initialGuess :: ([Pitch], GameState)
 initialGuess = (chord, chords)
@@ -122,4 +127,10 @@ allOctaves = [minBound .. maxBound]
 allNotes :: [Note]
 allNotes = [minBound .. maxBound]
 
+matches :: (Eq a, Show a) => [a] -> [a] -> Int
+matches xs ys = maximum permutationMatches
+  where
+    permutationMatches = map (pairwiseMatches xs) (permutations ys)
+    pairwiseMatches xs ys = length $ filter (uncurry (==)) $ zip xs ys
+
 --