feat: add comb sort

Author: danielzting

levels/comb_sort.gd

@@ -0,0 +1,48 @@
+class_name CombSort
+extends ComparisonSort
+
+const NAME = "COMB SORT"
+const ABOUT = """
+Comb sort is a variant of bubble sort that operates on gapped arrays.
+"""
+const CONTROLS = """
+If the two highlighted elements are out of order, hit LEFT ARROW to swap
+them. Otherwise, hit RIGHT ARROW to continue.
+"""
+
+const SHRINK_FACTOR = 1.3
+const ACTIONS = {
+    "SWAP": "Left",
+    "CONTINUE": "Right",
+}
+var _gap: int = array.size / SHRINK_FACTOR
+var _index = 0 # First of two elements being compared
+var _end = array.size # Beginning of sorted subarray
+var _swapped = false
+
+func _init(array).(array):
+    pass
+
+func next(action):
+    if array.at(_index) > array.at(_index + _gap):
+        if action != null and action != ACTIONS.SWAP:
+            return emit_signal("mistake")
+        array.swap(_index, _index + _gap)
+        _swapped = true
+    elif action != null and action != ACTIONS.CONTINUE:
+        return emit_signal("mistake")
+    _index += 1
+    if _index + _gap >= array.size:
+        if not _swapped and _gap == 1:
+            emit_signal("done")
+        _gap /= SHRINK_FACTOR
+        _gap = max(_gap, 1)
+        _index = 0
+        _swapped = false
+
+func get_effect(i):
+    if i == _index or i == _index + _gap:
+        return EFFECTS.HIGHLIGHTED
+    if i >= _end:
+        return EFFECTS.DIMMED
+    return EFFECTS.NONE

project.godot

@@ -39,6 +39,11 @@ _global_script_classes=[ {
 "language": "GDScript",
 "path": "res://levels/cocktail_sort.gd"
 }, {
+"base": "ComparisonSort",
+"class": "CombSort",
+"language": "GDScript",
+"path": "res://levels/comb_sort.gd"
+}, {
 "base": "Node",
 "class": "ComparisonSort",
 "language": "GDScript",
@@ -81,6 +86,7 @@ _global_script_class_icons={
 "BogoSort": "",
 "BubbleSort": "",
 "CocktailSort": "",
+"CombSort": "",
 "ComparisonSort": "",
 "InsertionSort": "",
 "MergeSort": "",

scripts/levels.gd

@@ -8,6 +8,7 @@ const LEVELS = [
     QuickSort,
     CocktailSort,
     ShellSort,
+    CombSort,
 ]
 const MIN_WAIT = 1.0 / 32 # Should be greater than maximum frame time
 const MAX_WAIT = 4